$2.50 (USA)
£1.20 (UK)
Volume 1, Number 2
Mar/Apr 1981
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eTic Tac Toe
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6 Book
Reviews
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Speed Up
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CAI INSTRUMENTS
Introduces the WIDGET" Series
of Peripherals for the ZX80
open the door to real computing.
"WIDGET" $49.95 | 'WIDGET^$99.95 Widgiprint
The Widget interface board allows your Тре Widgiprinter is а 28 column thermo
ZX80 to communicate with the rest of the printer that provides a hard copy of
world through both a serial RS/232 data results Нога your programs at a price you
bank and a parallel TTL input and can afford.
output parts.
а : Have you developed a unique option or
g 3 (8)
WIDGET” $99.95 Widgitape application tor your ZX80? We at CAI
The Widgitape is a revolutionary tape would be interested in discussing the
storage system that provides the features possibility of marketing your idea for you.
of high priced floppy disks at a fraction Contact us.
of the cost.
Unit Price
Remember this new “WIDGET” Series can open the
door to real computing for your ZX80.
Send Check, Money Order, or Credit Card WIDGET тыға КЛИН
Company to: WIDGIPRINT тек MM
WIDGITAPE
. TOTAL
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6 CAI Instruments, Inc. Card No. Visa
5 2559 Arbutus Court Mastercharge o
Е Midland, MI 48640 Exp. Date
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Address
City . * Зв ZIP
Or order by phone (517) 835-6145 giving your credit
said number. Michigan residents add 4% sales tax
The magazine for Sinclair ZX80 users
— ўс
March/April 1981
Volume 1, Number 2
36
40
10
16
ARTICLES & INTERVIEWS
Growth Plans and Pains................... АН! & Searle
An interview with Nigel Searle
Letters to the ЕдНог.......................... Headers
Corrections and tips
Interview With Alfred Milgram. ..........Ah/& Milgram
The president of Melbourne House speaks out
Crash Сигвог.................................. Truman
The saga continues
The Home Computer Market.................... Searle
Crystal ball gazing
Puzzles & РгоМетве........................ Townsend
HARDWARE TIPS
Micro ӉУшсе.................................... Капїег
Overcoming power line surges
Using the MicroAce with Sinclair Accessories. .........
Changes you can make to the PC board
Video Modifications for the ZX80......................
Reverse video and direct video
PROGRAMMING TECHNIQUES
A Display F ile in Machine Соде................. Logan
Speed up your screen displays
Memory Display................ TERR Cromley
Look into the memory of your ZX80
18.
20
47
48
Truth in Programming. .......................... Lubar
How to use Boolean operations
Data Statement Simulation..................... Turner
Your ZX80 can look like it has Data statements
PROGRAMS & SOFTWARE
Үуіддеі....................................... McGath
Simulation of a manufacturing company
АгїШ!егу.................................... Whetstone
Hit the target with your ZX80 cannon
Game оҒІйе...................................... Ahl
John Conway's classic game
Тіс Тас то... „о. авзон анана кекен Hoffman
Noughts and Crosses if you prefer
Making Music With the ZX80................... Forsen
Second best thing to a music synthesizer
REVIEWS & EVALUATIONS
ZX80 Рговагатв.................................. Stein
ZX80 Pocket Воок............................... Stein
ZX80 Magic Воок............................... Stein
Active Display and Breakout.................... Sutton
ZX80 Сотрапіоп................................ Stein
Disassembled Basic............................. Lubar
NEW PRODUCTS & RESOURCES
Product Ргеміем................................. Staff
Вевоигсвв....................................... Staff .
Publisher/ Editor-in-Chief
Editorial Director
Managing Editor
Staff
Advertiser
David H. Ahl
George Blank
Paul Grosiean
CAI Instruments
Basic Computer Games
Computer Music Record
Index to Advertisers
Associate Editor David Lubar Creative Computing
Secretary Elizabeth Magin Creative Computing Press
Production Manager Laura MacKenzie Creative Computing Back Issues
Typesetter Jean Ann Vokoun Lamo-Lem
Financial Coordinator William L. Baumann Linsac
Bookkeeper Patricia Kennelly LJH Enterprises
Customer Service Patricia Brown K. MacDonald
Order Processing Joan Swihart Melbourne House
Circulation Suzanne Guppy MicroAce
Frances Miskovich
Dorothy Staples Peripherals Plus
Phipps Associates
Rose Cassettes
Sinclair Research
SYNC
SYNC T-Shirt
March/April 1981
Outbound Engineering
Volume 1, Number 2
Page
31 SYNC is published bi-monthly for $10.00 per year
Cover 2 by Creative Computing, 39 E. Hanover Ave., Mor-
21 rs Plains, NJ 07950. Controlled Circulation
Cover 3 pending at Allentown, PA.
41
17 Postmaster: Send address changes to SYNC, P.O.
17 Box 789-M, Morristown, NJ 07960.
21
21 Subscriptions in USA: 6 issues $10; 12 issues $18;
23 18 issues $24. UK and foreign airmail subscrip-
7 tions: 6issues £10; 12issues £18; 181ssues £25. Call
11 (800) 631-8112 toll-free (in NJ, 201-540-0445) to
23 begin your subscription.
39
19 Copyright 1981 by Creative Computing. АП rights
23 reserved. Reproduction prohibited in any form.
3
33, Cover 4
15
Growth Plans and Pains
An Interview with Nigel Searle
Nigel Searle is Sinclair's man in Boston.
He is responsible for operations in the
United States and Canada of Sinclair
Research Ltd.
Recently Mr. Searle visited Creative
Computing and spoke with publisher David
Ahl, about the future plans for the American
operations of Sinclair.
N.S.: Asageneral plan I would like to see
us explore one new market every six month
period. I think that in four or five months
just about anybody who is thinking about
buying a personal computer (which is to
say the reasonably technically oriented
people, the same sort of people who have
already bought computers) must be aware
that there is an option of only spending a
couple hundred dollars to get started.
Market awareness is very high.
By the middle of 1981 I would like to
achieve a similar level of awareness among
people who make either purchasing deci-
sion or recommendations regarding com-
puters to be used in schools. Simultaneously,
we will focus our own mail-order efforts
on the home educational aspects of com-
puters in an attempt to reach beyond the
technical audience. Any parent who is
thinking of buying a computer for his
children will know that there is a low-cost
entry point, and will not have heard only
of Apple and TRS-80.
2
Itissurprising how many teachers there
are who read only educational publications.
Even though they may teach math or
computing, they don't read the computer
publications. At this point these teachers
are totally unaware of the fact that there is
such a thing as the ZX-80, and will remain
ignorant unless we do something about
that by addressing them through the appro-
priate channels.
My target for the first half of 1981 is to
achieve a level of awareness in the educa-
tional market. We would like to find a
single distributor who is capable of handling
this market with relatively little support
from us other than the product. We would
share all the knowledge we have gained
from our experience in other markets, but
we are hoping to achieve a rate of growth
that will be just about impossible to do on
our own.
The negotiations that we are having at
the moment don't look overly promising
and I don't want to suggest that anything is
going to happen soon. I believe that
traditional publishing companies would
make the best kind of partners for the
educational market because of they are
already selling to schools. They have the
sales force to do the job. They have the
ability to produce and publish the collateral
material, software etc. And like most
publishers they realize that their future
lies not only in ink and paper. The problem
is that their sales force is not necessarily
experienced in selling hardware. But you
must compromise somewhere.
D.A.: What arrangements do you have
with Image Software?
N.S.: What we are selling there is our
computer plus Image Computer Products'
Computer Learning Lab as a single package.
Our ads in the non-technical publications
next year are going to go very strongly on
this theme: selling the benefit of in-home
education, rather than selling the product
itself as we do now to the technical
audience.
It does no good to tell someone who
does not know what a computer is, that he
needs a computer. You’ve got to tell him
what it will do for him. Then he will
understand. If you are advertising in Popular
Electronics, the readers already know what
a computer can do for them; they want to
know what this particular product is. But
for the wider, non-technical market you
have to detail the benefits. I think that ina
year most of our mail-order ads, for what-
ever market—technical or nontechnical—
aren't going to look very much like ads for
hardware. They will look like ads for soft-
ware, because all the emphasis will be on
applications.
D.A.: That's where we are now with our
magazine positioning: it's applications and
software. We think that eventually there
is a much bigger market for that than for
SYNC Magazine
Learn how touse a computer
for $249. And keepthe computer.
Introducing the Computer Learning Lab, with the Sinclair ZX80 personal computer.
The Sinclair ZX80 is a powerful,
personal computer already in use in
tens of thousands of homes and busi-
nesses.
Now, for just $249“, the Computer
Learning Lab will teach you and your
children how to use this complete, ex-
pne computer right in your own
ome. And when you're done, you get
to keep the computer!
The Computer Learning Lab is a
self-paced course that teaches the ins
and outs of computers. It cuts away
jargon and mystique, taking you
straight into BASIC—the most com-
mon, easy-to-use computer language.
And the computer itself does the
teaching.
100 LESSONS MAKE
LEARNING EASY.
You just take the ZX80 out of the
box, connect it to your TV and an or-
dinary cassette recorder (connectors
are provided), and slip in the pre-pro-
S s de Learning Lab cassettes.
here's nothing extra to purchase.
You'll be wor ing with the computer
your very first day!
The cassettes take you through 100
ets о
& Sem
“Se
To order call toll free:
800-543-3000. In Ohio call:
800-582-1364. Ask for
operator #508. Phones
open 24 hours a day,
7 days a week.
se ре Гы that teach you how to
solve problems with the ZX80.
You learn by doing. By actually
working with the computer.
And the lessons are designed to be
fun and involving. You create your own
programs for games, code breaking,
interest calculation, and other topics.
Then you can apply the principles
youve learned to more complex
problems.
In fact, you'll be a master of the
ZX80. To use in your business, for
home budgeting, or just for fun.
We'll also send you a catalog full
of ready-to-use programs- from Loan
Amortization to Lunar Lander—avail-
able for as little as $6.95.
THE ADVANCED DESIGN
OF THE ZX80.
The ZX80 is the world’s first truly
portable computer. It features a touch-
sensitive keyboard and a 32-character
by 24-line display.
And it performs like a much larger
and more expensive computer. Single
keystroke entries make typing pro-
grams fast and easy. An automatic
error detection feature tells you if you
The complete package
includes the ZX80, a 128-page
guide to computing, a workbook,
six program cassettes, and two
blank cassettes for storing
your own programs.
Please send me —
Lab(s) with the ZX80 personal computer at $2
each (U.S. dollars).
I enclose check/money order payable to Sinclair Research Ltd. for S
Name
Address
бе
Occupation
Intended use of ZX80:
Have you ever used a computer? 0 Yes О No
make mistakes. And program editing
helps you correct them. Yet the com-
plete Computer Learning Lab, includ-
ing computer, is still several hundred
Bos
77
The Computer Learning Lab is a family
learning aid. Children 10 and above will
quickly understand the principles of
computing—and have Jun learning.
dollars less expensive than any com-
parable computer alone.
The ZX80 is backed by a 30-day
money-back guarantee and a 90-day
limited warranty with a national ser-
vice-by-mail facility. Extended service
contracts for the ZX80 are available for
a minimal charge.
To: SINCLAIR RESEARCH LTD., ONE SINCLAIR PLAZA, NASHUA, NH 03061.
Computer Leang
Please send me _______. ZX80 computer(s)
only, without the Learning Lab, at $199.95* each.
(Add $5.00 for shipping.)
*For Conn. deliveries, add sales tax.
Zip
Age
Do you own another personal computer? (1 Yes Ч No
Searle Interview, continued...
the hardware oriented magazine.
From a competitive standpoint, what
do you think the impact will be of the new
Commodore VIC: a four-color, 5K memory
computer with lots of capability for only
$300?
N.S.: It is obviously a much keener
competitor than anything that exists at the
present time. But we're not going to stand
still. One of the amazing things to me is
that we have sold as many computers as
we have, when all we offer is Integer Basic
and 1K bytes of RAM. Within a few months,
I hope we will have the 16K RAM and the
8K Basic, which will greatly expand our
market.
We feel that we are in a strong position
to respond to competition. If Commodore
were talking about a $200 price point for
the VIC, then I would be more worried
than I am. I think they will offer more
competition than anyone else in the market
at the moment. But I don't think we are
going to have much difficulty in saying,
"Here's our machine. Here's Commodore’s.
Look at the difference in price and look at
the difference in functions, and about the
only thing extra you get from Commodore
is color."
D.A.: What about some of the newer
Japanese entries? Are there any on the
horizon that look like competition?
N.S.: The amazing thing to me, again, is
that I don't see any signs from anyone
other than Commodore that they are
interested in the really low end of the
business. I don't know why Commodore is
the only company that has shown interest.
Perhaps this is because it hasn't, in general,
been doing very well here in the states.
Therefore it has nothing to lose; it's not
going to lose high-end sales by selling a` `
low-end machine.
We have proved that a market exists.
Our sales are sufficiently high that we have
discussed an advertising strategy calling
ourselves “The World's Number 1 In
Personal Computers." This means that
Sinclair has sold more personal computers
than any other company —even when you
include the models of all the other com-
panies. Frankly, I am not in any hurry to
make that claim, nor is Clive Sinclair. We
kind of like the fact that nobody else yet
seems convinced that a big market exists.
The longer they remain unconvinced, the
better I like it.
D.A.: You mentioned the 16K memory
and 8K Basic. Are they two separate plug-
ins?
N.S.: The 8K Basic is a single chip which
takes the place of the 4K chip on the main
board. You simply remove the cover, take
out the 4K chip and plug-in the 8K chip.
The 16K memory module plugs in to the
connector on the back of the board. It is in
a small case about 2 1/2” square.
D.A.: Do you have any projected prices
on those two?
4
N.S.: The 16K RAM will be $99.95. The
8K Basic almost certainly will be $39.95.
D.A.: I know no one likes to talk about
pricing, because you never know where
things will end up, but if competition heats
up substantially, would you meet it with
price or with something else?
N.S.: I don’t mind talking about it. We
buy our components from the same people
that everyone else does. If you are engaged
in a price war, then you have to be very
smart in your design, and you have to be
smart in your buying. You've also got to
be very careful that you don’t build at
yesterday's prices and sell at tomorrow’s
prices. I hope that we at Sinclair have
learned something from being in the
calculator business and that we will be
better equipped to cope with that sort of
downward spiral of prices if it turns out
that way.
I am probably more pessimistic about
that happening than are most people in
the business. I don’t think the personal
computer, once it becomes a truly consu-
mer-oriented item, is going to be very
different from the calculator in terms of
its marketing. Features will count for almost
nothing except at the initial stage. All that
anyone will care about is that they get the
cheapest computer. Because they are dead
scared that they will buy one for $50 and
tomorrow a friend will buy one for $35
and they will feel like an idiot. That is all
that motivated the drive in calculator prices
down to $29.95 and then $19.95.
There eventually emerges a price that
people are willing to pay and they want
the best you can give them at that price. If
they can get everything they want then
they don’t want to pay more than that
critical price. I think we are well equipped
to buy components to design the product
using our experience with the calculator
business. I think we are well equipped to
survive that kind of price war and, hopefully,
we are smart enough to look ahead to see
what kind of product we will need afterward
to compete with the Japanese —if indeed
itis the Japanese who come along afterward
as they did in the calculator business.
The other thing about the calculator
business that may be true for the computer
business is that there came a time at various
stages in the calculator business where
you couldn't sell a calculator unless it was
of a particular type. I have said that people
weren't feature conscious, but they were
in a very unselective, media-directed way.
There were articles about how to buy a
calculator — they would say “4о not buy а
calculator with disposable batteries, it must
have an A/C adaptr and recharger." That
remained true for quite a long time until
Rockwell brought out the first calculator
that ran off a single nine-volt battery. It
was far superior to a rechargable battery
system.
But because people were told not to
buy a throw away battery system because
"they will run down in no time at all and
will cost you a fortune" people still believed
that to be true even when they had a single
nine-volt battery unit available to them.
Then there was a time you couldn't sell a
calculator unless it had a percentage key,
or a memory key on it. Despite the fact
that of all the people who bought calculators
with a memory key only 2.576 used them,
no one would buy one that didn't have a
percentage key; they read in Consumer
Reports that you should have one.
Itis dangerous to say that the computer
business is going to be just like the calculator
business. It will be different, and it is
probably pointless to make comparisons
with other products and other markets. It
is, however, going to be more like the
calculator business than people think.
D.A.: I feel that in the market for the low-
end computer — not just the Sinclair, but
the VIC, Mattell, APF etc.—a big mistake
is being made in trying to initially sell the
broad consumer market. The best market
for these products is made up of people
who already have a computer— those who
have bought an Apple, Altair etc. — and
don't want their kids playing with it all the
time. Or they want a state-of-the-art unit
for themselves. |
N.S.: Absolutely. In a sampling of thd
people who bought our computer from an
ad in Popular Electronics, 38% already
owned a personal computer. But, obviously,
in the long run we do not want to sell
exclusively to people who already own a
personal computer, because then we can
only sell as many units as all other manufac-
turers put together.
D.A.: My pointis that I believe a computer
is still a new enough device that someone
buying it wants a recommendation from
someone else who has one.
N.S.: Perhaps. But there may be another
way. You can't convince a large part of
the market until they have actually used
the machine. Our consumer market adver-
tising within the next couple of months
will start to go on the attack. Rather than
hide our free trial offer, money-back
guarantee in the fine print, we will put it
right up front. So much up front that it
might well be the headline. We've been
kicking around ideas at the advertising
agency with lines such as "You can't try
the Sinclair for 10 minutes in any store,
but you can try it for 10 days in your own
home at no cost." Just using the old
fashioned mail-order ploy that says "Please,
please, take one and try it. If you don't like
it send it back. But please try it.” We think
that trying it will convince the customer to
buy it. []
SYNC Magazine
Lect
Our Face is Red!
Dear Editor:
I recently received my first copy of Sync
magazine and I was very pleased. However,
I would like to point out a few things I
found wrong.
1. Page 18— Nicomacus — Line 100 should
read 70*a t- 21*b + 15*с. As listed, this pro-
gram correctly deduces numbers only from
7 to 104 or between 6 and 105.
2. Page 35— Multiplication Tables— Line
330 needs a semi-colon after A$ to run
properly. Line 335 should have a comma
instead of a period in the beginning of the
print message.
3. Some of the listings require the use of
spaces or changes in the print format in
order for the messages to print out properly
on the tv screen. Also, it would be a good
idea to let your readers know if a listing
will run in 1К memory. Some of your
programs occupy so much memory, they
will not run. For example; Page 36 — Basic
Accounting — As listed I could only enter
up to line 2055 before I ran out of memory.
To be sure, the above items are only
minor in nature, but I would appreciate
hearing from you. All in all, I find the
magazine to be an excellent one which I
shall continue to subscribe to. Thank
You.
John A. Sampson
College Point, NY
March/April 1981
Four Tips for
MicroAce Owners
Dear Editor:
These suggestions are based on my experi-
ence with the MicroAce.
1. Lacquer thinner and an old toothbrush
are useful for cleaning solder flux from
the PC board.
2. Changing R24 from 1K to 4.7K increases
the sensitivity of the cassette input but still
holds pin 2 of U11 close enough to ground
for an adequate noise margin.
3. The crystal oscillator did not always
start, especially when the computer was
first plugged in. This problem was eliminated
by a 100K resistor from pin 12 of U18 to
ground (across C8). This is a leakage resistor
which apparently draws off an accumulating
charge on pin 12.
4. The keyboard input IC (U11) blew twice
from a static charge while I was using the
computer on a carpeted floor. This 7415365
is replaceable by а 7415367, which Radio
Shack carries.
David A. Cromely
Channel 2 Interference
Problem Cure
Dear Editor:
Enclosed is my check for a one year
subscription to your SYNC magazine. Hope
it is as good as your brochure states.
There are two items I'd like to relate
about my experience with my ZX80. First,
as you know, the computer is tuned to
operate on Channel 2. Here in Atlanta, I
live close to the station, and I could not
display on this channel without a very
objectionable amount of interference. I
hoped there was some way to cure the
problem, so I called the "technical rep" at
Sinclair. His solution was-use the computer
in the basement-find a room with metal all
around-or move. Some help! Some old
timers at work recommended I try inserting
iron or brass in the tuning coil. By this
time I had very carefully removed the
cover from the non-adjustable tuner.
Although the iron and brass did affect the
frequency, it was not enough. A second
idea was to very gently spread a few of the
windings of the coil. Praise the Lord! It
worked like a charm. I was able to to tune
it to Chan. 3 with no problem at all. I
closed up the unit and Гуе been on a good
clear screen ever since. The second item
concerned the cassette recorder. I set the
controls, etc. just like the manual said.
About 50% of the time I could not load
from the cassette recorder to the computer.
That is, until I tried the volume control
setting at less than the maximum as recom-
mended in the manual. In my case I can
leave the setting on 7 and save and load
with virtually no failures.
Well, thats it. Hope this info saves
someone the frustrations I went through.
R.E. Henneberg
An Interview with Alfred Milgram
D.A.: Nigel Searle made an interesting
comment about marketing kits by mail
order. He said that kit builders in the U.K.
generally knew what they were doing and
there was very little trouble or returns.
whereas in the U.S. it is entirely different.
People buy a kit expecting it to be like a
leathercraft or model car kit that any kid
can assemble. Nigel told me of a person
who called after buying a kit and asked,
“What’s a soldering iron?" In the U.S.,
MicroAce sells a version of the ZX80.
While there's not a lot of soldering or
assembly to do, people have to know or do
have to handle the integrated circuits
reasonably carefully. Static electricity is a
real enemy, at least until the chip is installed.
They also have to know that you can't use
the same sort of soldering gun that you use
for your plumbing repairs to solder a printed
circuit board.
A.M.: How is MicroAce distributing their
product here? I don't see them in the
magazines, they are not visible.
D.A..: Strictly by mail order. They have
been restricted by Sinclair from advertising
in a certain group of publications that
Sinclair has reserved for itself. Sinclair has
more or less picked the top one or two
magazines in each individual field and left
the balance to MicroAce which is a policy.
in my mind, to defeat MicroAce. What is
the story on that? What actually happened
between Sinclair and MicroAce?
A.M.: The people at CompShop have a
history of copying. The guy behind Micro-
Ace is the guy who runs CompShop in the
U.K. Atone stage they couldn't get enough
supplies from Ohio Scientific, so they
redesigned the OSI Superboard and got
the ROM from Microsoft. Now they are
paying the royalties to Microsoft, have
redesigned the board and are selling it as
the U.K. 101.
Then the Sinclair came out and they
figured here was a golden opportunity to
save on development costs and come out
with effectively the same machine. They
copied the ROM, byte for byte, moved the
circuits about, cleaned it up a bit, and
moved the RAM memory away from the
heat sink. The case is black instead of
white, and they were going to market it in
6
the U.K. for £ 50 as opposed to £ 770, the
price of the ZX80. Sinclair got upset and
sued them for breach of copyright. In the
case two items were put up for breach of
copyright: stealing the ROM and the
keyboard. The judge said in effect, "I can't
read the ROM. Nobody can read the ROM.
The ROM is not copyrightable. But the
keyboard: that's the same keyboard, anyone
can see that." They settled out of court.
D.A.: SoSinclair then licensed them to do
a kit version?
A.M.: They allowed them, because at
that stage they had gone quite a ways into
manufacturing, and were already com-
mitted, with many thousand ROMs and
printed circuit boards and all the rest of it.
They couldn't afford to pull out of it at
that stage. So Sinclair allowed them to
market it as long as they didn't sell it in the
U.K.. only sold it in kit form, and complied
with the restrictions on advertising.
D.A.: From what I gather there are people
at Sinclair that would like to design periph-
erals and add-ons that specifically would
not fit the MicroAce.
A.M.: One of the reasons they told me
that they were not prepared to let the new
ROM out, was that they did not want to be
ripped-off in the same way. I don't think
they can really avoid it in the long run.
Because basically anyone who has a Micro-
Ace can go and buy a new ROM from
Sinclair and pop it in.
D.A.: Will it fit?
A.M.: Yes, because it is a straight copy.
The only thing that MicroAce has done is
to add another 1K on board. Apart from
that it is exactly the same machine. It has
the same routines which all run in the
same places, the same operating system,
the same number of chips, it is basically
the same machine. I can't see how Sinclair
can design anything that would not be
compatible with the MicroAce.
D.A.: Tell me a little more about your
plans. You mentioned two books, one on
machine language programming.
A.M.: We've done exceptionally well in
the U.K. with our first book, 30 Programs
For the ZX-80, because it seems that the
market is mainly people who have not
bought a computer before and they don't
know what to do with the machine. We
are finding that a lot of buyers are people
who don't even know how to enter a
program. They are are just following blind,
letter for letter. But the cost of the machine,
in our mind, made it so it wasn't worth
marketing cassettes in the U.K. There are
a lot of people who are marketing cassettes
in the U.K. but they tend to have six or
eight programs on one cassette.
There is a subgroup of users who are
very interested in going further, and using
the machine as a learning tool in developing
their own programs. It is for those people
that we are doing machine language pro-
gramming and programming techniques.
Programming Techniques is fairly basic.
It uses the specific capabilities of the
Sinclair. You could just buy a book on
Basic programming. but the language isn't
quite the same because you are working
with a subset. So you must know how to
cope with certain limitations —not having
a step function in loop. for example. The
biggest difference is the totally dynamic
display screen where the display shrinks
and expands as you use the machine. So
you just can't poke in and out of the screen
or easily move things about. Then there
are the people who want to use machine
language programming for its user sub-
routine capabilities. But again you need
special advice beacause there is no RAM
protected area.
There are ways of entering machine
programs and yet being able to save them,
because when you save a program on
cassette you can save all the variables as
well. So you can retain a machine languge
program on tape and use it later.
D.A.: How do you save machine languge
programs?
A.M.: In our 30 Programs book. several
programs utilize machine language routines.
We show two different ways of loading
those routines into the program. The two
simplest ways are to load it into a REM
statement or to load it into a variable.
D.A.: Into a Remark statement? A machine
language routine? How can it then be
used?
A.M.: You make your Remark statement
the first statement of the program. So you
SYNC Magazine
Interview, continued...
know its location. You poke the values
into the Remark statement later on. Then,
because you know absolutely its location,
you can call up the subroutine. If you use
a variable to poke it into, you have to
remember that the computer is dynamic
and every time you call a new variable it's
likely to shift in position. So you have to
peek into the location which tells you where
the variable storage starts.
D.A.: We received one article, in which
someone showed how different characters-—
graphic characters—could be put on the
screen to create a moving graphics display.
It emphasized that you had to peek to the
beginning or look at the beginning of the
graphics display in the same statement
that you poke because of the dynamic
allocation.
A.M.: That’s true unless you have defined
all of your variables first. However, you
must remember that loop variables have a
separate definition from your regular vari-
ables (because they are stored differently
in the machine).
D.A.: Do you think that the 8K Basic will
be any more standard?
A.M.: Itisastep closer. It has step functions
available, trigonometry and other scientific
functions, decimal numbers, and string
arrays. All of those things mean that the
subset is that much closer to Microsoft
Basic. What you don't have is the ability to
define variables and integers, which I think
"This Book is Excellent!"
— Clive Sinclair
is very stupid, because you are wasting a
lot of memory when you are just using
ordinary integer arithmetic.
D.A.: Where do you see Sinclair going in
two or three years? Do you see prices
coming down, etc?
A.M.: I think Clive Sinclair is going to
move out of the computer market. I think
that what he should be doing is moving
into the small businessman's cheap com-
puter. Because he has a reputation in the
U.K. of being able to come out with a
product which is technically brillant, but
very cheap and very tinny. That's what he
does, and he does it very well. If he came
out with a computer for £300 which would
be very basic —a 16K machine with a one-
page word processor, that could handle
invoicing for 30 accounts or whatever you
can get into 16K, and a very cheap printer
for - 200, it would sell an immense number
of small business machines. But I don’t
think he sees it this way. I think he is going
to move out into other markets.
Sinclair is the first in the personal
computer field who has come out with
such a low price. But very soon there are
going to be others who are going to offer
better products for the same price. And
he won't be able to compete any more. He
has been able to do well because he was
first. And he has shown the potential that
exists both in terms of technology and in
terms of marketing. Just as he wasn’t able
to keep up in electronic watches or pocket
calculators, I don’t think he will be able to
keep up in the computer field.
D.A.: Word reaches us that the next big
thing that Sinclair is working on is “flat
screen television.”
A.M.: He has been working on that for
years and I think that he probably will do
1t
D.A.: They claim that the flat screen
television is being built and sets will be on
the market by this December.
A.M.: I will be surprised if it is that early,
because he has always had a problem with
delivery. He will probably demonstrate a
model by December.
D.A.: Isyour machine language program-
ming book going to take people by the
hand assuming they don't know anything
about programming at all.
A.M.: The people who are involved in the
7,Х-80 users club in the U.K.—and they
know the Basic very well — still don't know
how the user function works. They don't
understand how you get a machine language
program to run. If that is at all typical, and
I think that it is, then the people who have
now taught themselves some Basic want
something different. They bought the
computer because they think it is time to
learn about computers, and they don't
understand the way the machine language
іп the computer works. The ZX-80 machine |
language code is a very powerful one but |
it is also very complex. It is a very useful
code; you can do a lot of things with it.
Our book will try to put it within the grasp
of every reader. Г
The unique book contains 30 programs all designed to fit in the basic 1K version of
the SINCLAIR ZX80!!
With this book you will realise that the ZX80 is more powerful than you ever imagined!
112 pages packed full of solid information!
BLACKJACK — actually contains a full pack of cards, shuffles them, keeps track of
the dealer and player totals, and the money bets, all within 1K.
Dr. Tn — a truly conversational program: DR. ZX-80 is your personal computer
analyst.
LINE RENUMBER - an invaluable program which automatically renumbers lines
and puts order to your programs.
MEMORY LEFT — an incredible routine especially useful with only 1K, which lets
you know to the byte how much memory is left. This also illustrates USR routines.
GOMOKU — the computer challenges you to this complex Japanese game, incredibly
this program including display of the 7 x7 board fits into 1K — it only does so because
it uses the display as memory!
Other programs included are HORSE RACE, LUNAR LANDER (with moving spaceship
display, NOUGHTS AND CROSSES, NIM, SIMPLE SIMON, HANGMAN, LIFE:
MASTERMIND, PINCH and 16 others!
available $ 1 4 95 Other Шалды
> include:
by mail (plus ни ZX80 Machine Language
order only and handling) Programming
MELBOURNE HOUSE Orders to: IMAGE COMPUTER PRODUCTS
PUBLISHERS 615 Academy Drive, Northbrook, III. 60062.
Please send me copy/ies of '30 Programs for the ZX-80: 1K
Please encolse
Check or Money Order
NAME for $15.95
ADDRESS
March/April 1981 7
(ff
^
Owners of the Sinclair ZX80 and Micro-
Ace rapidly discover that interruptions of
power can cause headaches, not to mention
the necessity for re-keying programs. If
you live in the "Sunshine" state. Florida,
you also have to contend with “Florida-
Flicker & Flash,” better known as the local
utility company. They achieved their
reputation by the repeated switching
between feeder lines, causing lights to
flicker, creating all sorts of problems for
computer users.
After re-keying several programs into
my MicroAce, the Micro-Juice project was
born. Most major computer installations
use large and expensive line conditioning
transformers, filters, and if the area or
data is important enough, a device called
a U.P.S. The uninterruptable power supply
is illustrated in a simple block diagram
(figure 1), and generally consists of a device
to convert direct current from a storage
battery to alternating current, with a
switchover network to allow it to take
over if commercial power fails. There are
several variations on this basic circuit, but
generaliy the U.P.S. allows operation for
up to one hour, depending on current
requirements, and the size of your budget.
This protection doesn’t come cheaply,
because U.P.S. systems start at over two
hundred dollars.
It makes little sense to spend two-hundred
or more dollars for a ZX80 U.P.S., but
Micro-Juice serves the purpose for about
$10. Fortunately, the ZX80 and the Micro-
Ace were well designed for this addition.
Tests on my MicroAce showed that the
unit drew approximately 330 mA in use,
and the d.c. input from the power supply
Elliott S. Kanter, 1704 Raleigh Ave., Holly Hill, FL
32017.
Elliott S. Kanter |
was about 14 Volts unloaded, with the on-
board five volt regulator handling the
transition to the five volts the ZX80 needs.
All we wanted to do was to insure that
the computer and its memory would remain
powered during a power flicker or loss. To
do this we needed a source of d.c. some-
where between 5 and 15 volts, supplying
330 mA for about an hour. The transition
would have to be so quick as to not disturb
the memory. Another requirement was
that the Micro-Juicer had to be easy to
build and duplicate, using easily obtained
parts, and represent as good a value as the
computer itself. Considering all those
requirements, I was both pleased and
surprised to be able to come up a circuit
meeting all these needs.
Examining the circuit in figure two, we
see that Micro-Juice is somewhat similar
to the block-diagramed U.P.S. system. Both
sense a drop of commercial power and
immediately apply an alternate power
source. Micro-Juice, however is simpler
and costs less, relying on 9 volt alkaline
batteries, which provide power for over
an hour.
The circuit is mounted in any convenient
box, offering the builder the option of
bypassing the two input jacks, and simply
cutting the power cable from the wall-
supply, feeding it directly into the cabinet.
If you use this approach, make use of
strain relief grommets and take careful
note of polarity — the tip is positive, and
the ring is negative.
After assembling the circuit and checking
both the polarity of the connections for
input and ouput power, and the orientation
of the diodes, connect Micro-Juice to your
ZX80. With the normal a.c. system in
operation the cursor will be visible. When
SYNC Magazine
INVERTER
WITH
BATTERY
CHARGER
POWER OUT
BATTERY SUPPLY
Figure 1. Block Diagram, U.P.S.
Parts List
274-251 — Л, J2 two conductor, open
you pull the power supply from the wall
outlet the ‘K‘ remains.
Micro-Juice is not a portable d.c. supply
capable of running the ZX80 indefinitely,
but it is a fail safe device to guard your
program from accidental power interrup-
tions. Another convenience of this system
is that all required parts are available at
your local Radio Shack. The parts numbers
are listed below. О
POWER
IN
d
B1,B2
CONNECT IN
PARALLEL
Figure 2 — Micro-Juice
circuit 1/8 inch phone jacks.
274-286 — P1, P2 two conducter, 1/8 inch
phone plugs.
276-1101 — D1, D2 diodes, at least
50РТУ 1А.
23-553 — ВІ, B2 or equivilant 9 volt akaline
batteries.
270-233 — Cabinet, 5 1/6 X 25/8 X 1 5/8
inches.
Solder
Assorted wire
NEGATIVE
м POSITIVE
[Рт р2 0 ==
March/April 1981
Using the Microace with
Sinclair Accessories
1 — Repair cuts shown & remove links presently installed.
2— Cut tracks where shown.
3— Make link between A & B.
4— Make link between X & Y.
Solder Side
To illustrate modifications required to run new 8К ROM chip
Cut the 2
traces
shown here
© о
H oc
Repair "y “т.
жы TIR — SI 7 1 ps
00000000
0000000
The 16K RAM Module: 7 1
The 16K RAM Module is completely жн both links and repair the cuts that we have
compatible with the MicroAce ІК Kit; __ made using a small piece of wire. (see
the unit can be simply plugged on the y above).
back. If the RAM Module is to be fitted to The next stage is to cut the track that goes
a 2K Kit then the extra 1K should be to pin 13 of the ROM chip and the track
removed along with U17. Please be sure == that goes to pin 14 of the ROM chip as
that the 2K2 resistor has been installed in shown above
place of R16. The Module may now Бе ™ Now use a small piece of wire to make a
plugged onto the back of the machine. m link between pin 13 of the ROM chip (on
е the PCB) and pin 18 of U6.
The 8K Basic ROM: » Also make a link using another piece of
The MicroAce kit comes with two track wire between pin 14 of the ROM chip (on
cuts on board, i.e. both sides of pin 21 of the PCB) and pin 3 of U6.
the ROM chip. You also need to make The new ROM chip may now be plugged
two links on the board. into its socket and power applied to the
Before installing the new ROM chip, remove board.
10 SYNC Magazine
EEE
The unique
and valuable x
components of the MicroAce
The MicroAce is not just another personal
computer. Quite apart from its exceptionally low
price, the MicroAce has two uniquely advanced
components: the powerful BASIC interpreter, and
the simple teach yourself BASIC manual.
The unique versatile BASIC interpreter offers
remarkable programming advantages:
€ Unique 'one-touch' key word entry: the
MicroAce eliminates a great deal of
tiresome typing. Key words (RUN, PRINT,
LIST, etc.) have their own single-key entry.
€ Unique syntax check. Only lines with correct
syntax are accepted into programs. A cursor
identifies errors immediately. This prevents
entry of long and complicated programs with
faults only discovered when you try to run
them.
€ Excellent string-handling capability — takes up
to 26 string variables of any length. All strings
can undergo all relational tests (e.g.
comparison). The MicroAce also has string
input — to request a line of text when
necessary. Strings do not need to be
dimensioned.
Up to 26 single dimension arrays.
FOR/NEXT loops nested up 26.
Variable names of any length.
BASIC language also handles full Boolean
arithmetic, conditional expressions, etc.
€ Exceptionally powerful edit facilities, allows
modification of existing program lines.
€ Randomise function, useful for games and
secret codes, as well as тоге serious
applications
€ Timer under program control.
А Micr
The [Місгобсе]
€ РЕЕК and POKE enable entry of machine code
instructions, USR causes jump to a user's
machine language sub-routine.
€ High-resolution graphics with 22 standard
graphic symbols.
€ All characters printable т
program control.
€ Lines of unlimited length.
reverse under
‘Excellent value’ indeed!
For just $149.00 (excluding handling charge) you
get everything you need to build a personal
computer at home... PCB, with IC sockets for all
ICs; case; leads for direct connection to a cassette
recorder and television (black and white or color);
everything!
Yet the MicroAce really is a complete, powerful,
full-facility computer, matching or surpassing other
personal computers at several times the price.
The MicroAce is programmed in BASIC, and you
can use it to do quite literally anything, from playing
chess to managing a business.
The MicroAce is pleasantly straightforward to
assemble, using a fine-tipped soldering iron. It
immediately proves what a good job you've done:
connect it to your TV ... link it to the mains adaptor
... and you're ready to go.
Fewer chips, compact design,
volume production-more power
per Dollar!
The MicroAce owes its remarkable low price to its
remarkable design: the whole system is packed on
to fewer, newer, more powerful and advanced LSI
chips. A single SUPER ROM, for instance, contains
the BASIC interpreter, the character set, operating
system, and monitor. And the MicroAce 1K byte
Licenced by Sinclair Research Ltd.
ocompu
for everyone at
- a new generation of
miniature computers
A COMPLETE COMPUTER
for $149.00 for 1K Kit
Post and Packing FREE
(Add 696 Tax for Shipments inside California)
RAM (expandable to 2K on board) is roughly
equivalent to 4K bytes in a conventional computer
— typically storing 100 lines of BASIC. (Key words
occupy only a single byte.)
The display shows 32 characters by 24 lines.
And Benchmark tests show that the MicroAce is
faster than all other personal computers.
No other personal computer offers this unique
combination of high capability and low price.
The MicroAce teach-yourself
BASIC manual.
If the features of the BASIC interpreter mean
little to you-don't worry. They're all explained in the
specially-written book free with every kit! The book
makes learning easy, exciting and enjoyable, and
represents а complete course in BASIC
programming-from first principles to complex
programs. (Available separately-purchase price
refunded if you buy a MicroAce later.)
A hardware manual is also included with every kit.
The MicroAce Kit:
$149.00 with IK COMPLETE
$169.00 with 2K
Demand for the MicroAce is very high: use the
coupon to order today for the earliest possible
delivery. All orders will be despatched in strict
rotation. If you are unsuccessful in constructing
your kit, we will repair it for a fee of $20.00, post and
packing FREE. Of course, you may return your
MicroAce as received within 14 days for a full
refund. We want you to be satisfied beyond all
doubt — and we have no doubt that you will be.
Sockets for
TV, cassette
Z80 A microprocessor
chip, widely recognised
as the best ever made. recorder, contains...
UH Е power А
Ехрапѕіоп supply.
Connector TV SUPER
modulator ROM. L
Rugged,
RAM flush
Clock. chips ush,
Keyboard
Your MicroAce kit
Printed circuit board, with
IC sockets for all ICs.
Complete components set,
including all ICs-all
manufactured by selected
world-leading suppliers.
€ New rugged keyboard,
touch-sensitive, wipe-clean.
€ Ready-moulded case.
H Quantity
€ Leads and plugs for NN MicroAce КП Ts. | 9199009 KENNEN
H | | MicroAce Kit 2K | $169.0 | |
[ С БЕНЕН С О
connection to domestic TV
and cassette recorder.
(Programs can be SAVEd
and LOADed on to a
portable cassette recorder.)
@ Mains adaptor of 600 mA
at 9VDC nominal 1
Description
Shipments inside California
add 696 TAX
unregulated.
€ FREE course in BASIC
programming and user
manual.
[Еа check, Money Order or quote your Credit Card опо: а аа 8
Send Check, Money Order or quote your Credit Card No. to:
MicroAce 1348 East Edinger, Santa Ana, California, Zip Code 92705.
В or phone (714) 547 2526 quoting your Credit Card Number.
Unit Price
1K Upgrade Kit $29.00
TOTAL
JOIN THE REVOLUTION - DON'T GET LEFT
BEHIND - ORDER YOUR MICRO ACE NOW!
TOTAL Amex.
Diners
Check
Money Order
Master Charge
Visa
Card No.
Exp. Date
Video Modifications for the ZX80
12
REVERSE VIDEO
It is possible to directly invert the
video signal that leaves the ZX80 and
drives your TV. This is done by accessing
pin 9/1С9, instead of pin 7/IC9, as the
input (pin 4) to IC20. Below are the in-
structions for the modifications.
Remove the entire case from the
ZX80. In the right center section of the
back of the PCB you will see an etching
that looks like this:
" DIRECT VIDEO
Nt n
A С It is possible to connect a video moni-
tor directly to the ZX80. This is accom-
plished by passing the RF modulator and
adding a small amount of buffer circuitry.
This circuit also reverses the video signal
which can be controlled by the RV
switch shown earlier.
Open the ZX80. Look at the modu-
First, cut the trace between points A
and C with a razor blade or exacto knife.
Now install the following circuit:
RV switch lator. (See Below.)
B
A
<-------- SPDT Switch T
с men
Drill an appropriately sized hole in the
case. Mount the switch. Close up the case
and power-up the system. You will notice
that toggling the switch will cause the
video to invert. Tapping the video lead on R30 (see
Schematic), you should run it through the
buffer circuit shown below:
3.3K Vcc
2N2222 or similar
Video on R30
68.1. Monitor
2.7K
7513.
SYNC Magazine
Howto Produce a Display File
Using Machine Code.
The ZX80 is supplied with a 4K ROM
that contains the Basic interpreter. There-
fore the average user will use the PRINT
command of the Basic language to produce
his pictures on the T.V. screen. However
Basic is fairly slow.
For example the following Basic program
draws a simple rectangular playing area,
that could form part of many games, takes
over 2 seconds to RUN.
10 FOR I=1 TO 32
20 PRINT “@”;
30 NEXT I
40 FOR J=1 TO 10
50 PRINT "B;
60 FOR I=1 TO 29
70 PRINT “gy”;
80 NEXT I
90 PRINT "g^
100 NEXT J
110 FOR I=1 TO 32
120 PRINT “№”;
130 NEXT I
(shift A) Top line
(space)
Of course the above program could be
rewritten using many little tricks and as a
result could be quite fast, but it would
probably use a lot of valuable memory.
As machine code routines are very fast
it is obviously useful to be able to replace
the slow parts of Basic programs with
machine code routines.
This article goes through the steps
Dr. LS. Logan, 24 Nurses Lane, Skellingthorpe,
Lincoln LN6 OTT England.
March/April 1981
The rows
Bottom line f
How Is It Done ?
Dr. l.S. Logan
involved in producing a Display File under
machine code, and will show how the above
Basic program can be replaced by a machine
code routine called using a statement such
as:
20 LET K=USR(16427)
However the structure of the normal display
file must be discussed first.
The Display File: In the ZX80 the display
file is the part of the RAM which holds the
next picture to be shown. A complete
picture is made up of 24 lines which can be
from 0 to 32 characters in length. The
display file has an initial delimiting "118",
and another delimiting “118” to mark the
end of each line.
When a Basic program is RUN the display
file can initially be considered to be empty
and as each PRINT statement is interpreted
the Display File is filled with the required
characters.
For example the display file produced
by the Basic program above will have the
ollowing structure:
== Ist. Line 2nd. Line
32 shifed A’s
3 m '
The part of the display file after the
12th. Line has been left empty in the diagram
to show the place where further PRINT
statements would add their characters.
However if the Basic program is finished
(oris stopped) then the end of program
RUN routine will complete the display file
by adding to the Display File the number
of “11875 as specified in the line counter
system variable 16421), and then adding
the required E-LINE. The Display File
will be complete as it holds the characters
that will form 24 lines.
Once the above details have been under-
stood, then it follows that the machine
code routine below must result in a Display
File of exactly the same structure.
An Outline Flow Diagram: There are three
parts to any machine code routine construct-
ing a Display File. These are shown in the
diagram below, and each part will discussed
in turn.
3rd.—11th. Lines
As
1st.Line
30 spaces
12th. Line —» _
PICK UP
DISPLAY FILE
POINTER
CONSTRUCT
PICTURE
RESET
SYSTEM
VARIABLES
Pick up Display File pointer: The Display
file pointer is held as System Variables,
16396 & 16397, so this part the program is
very straightforward. The HL register pair
is loaded with the contents of locations
16396 & 16397, and then incremented to
point to the location required for the starting
character of the first line.
Construct picture: Following the example
of the BASIC program that drew a simple
Assembler language
LD HL, (D-FILE)
INC HL
rectangle, a machine code routine must
be written to draw a similar rectangle. End
of line delimiting “118° must be added as
required. The following algorithm is just
one solution of many, and it has been
chosen as it closely copies the Basic
program. It is not a very efficent algorithm
but it is fairly easy to follow.
N.B. The decimal machine code instruc-
tion “118” has purposely been avoided, as
the ZX80 will interpret it as an end of line
delimiter if the machine code is stored ina
REM statement. (see Chart 1)
14
Chart 1
42, 12, 64
39
Edge
Rows
Line
Space
B-Line
Edge-2
LD B, #32
LD (HL), #9
INC HL
DJNZ, EDGE
LD A, #117
INCA
LD (HL), A
INC HL
LD B, #10
PUSH BC
LD (HL), #9
INC HL
LD B, #30
LD (HL), #0
INC HL
DJNZ, Space
LD (HL), #9
INC HL
LD A, #117
INCA
LD (HL), A
INC HL
POP BC
DJNZ, Line
LD B, #32
LD (HL), #9
INC HL
DJNZ, Edge-2
LD A, #117
Decimal machine code
54,9 (the shifted A)
35 (move to next character)
16,251 (loop until row finished)
62,117 (the top row delimiter)
60 (117 + 1 = 118)
119 (enter delimiter)
35 (move to next character)
6,10 (there are 10 rows)
197 (save the row number)
54,9 (the shifted A)
38 (move to next character)
6, 30 (30 spaces/row)
54, 0 (enter а ‘space’)
35 (move to next character)
16, 251 (loop for 30 spaces)
54,9 (the shifted A)
к (move to next character)
62, 117 (a row delimiter)
60 (117 + 1 = 118)
119 (enter delimiter)
35 (move to next character)
193 (collect row number)
16, 234 (loop for 10 rows)
6, 32 (32 characters/row)
54,9 (the shifted А)
39 (move to next character)
16,251 (loop until row finished)
62,117 (a row delimiter)
60 (117 + 1 = 118)
119 (enter delimiter)
35 (move to next character)
(32 characters/row)
Reset System Variables: There are three
system variables that require to be reset
after any picture.
The DF-EA and the DF-END need to be
filled with the address of the first free
location in the Display File, i.e. the current
contents of the HL register pair, and the
line counter at 16421 must be filled with
the value required. (The row counter at
16420 may also need to be reset, but this is
not required in the present example.)
System LD (DF-EA), HL
LD (DF-END), HL
LD A, #11
LD (LINE COUNTER), A
RETURN
34, 14, 64
34, 16, 64
62, 11
50, 37, 64
201
(rows unused)
SYNC Magazine
ч
Entering The Machine Code Routine: The
above machine code routine has 64 instruc-
tions and all these instructions must be
loaded into the RAM before the routine
can be called. There are many ways in
which machine code routines can be stored
in the ZX80 but the method used below
prevents the routine from being overwritten.
However never ‘i to LIST the whole
program. (ме. try it. After you have
SAVED it}
Now ent^, the following program.
Screen Display:
42 12 64 35
6 32 54 9
do 16 251 62
117 60 119 35
6 10 197 54
9 22 6 30
54 0 35 16
251 54 9 35
62 117 60 119
35 193 16 234
6 24 54 9
29 16 251 62
117 60 119 32
34 14 64 34
16 64 62 Ц
. 50 37 64 201
Machine code loader program:
10 REM 64locations (do not use spaces!)
20 LET CHECKSUM = 0
30 FOR I = 16427 TO 16490
40 INPUT A
50 LET CHECKSUM = CHECKSUM + A
60 POKE I, A
70 PRINT PEEK (1),
80 NEXT I
90 PRINT “CHECKSUM = ”; CHECKSUM
The following lines also need to be entered
and afterwards deleted (line number and
Newline) so as to scroll line 10 off the
screen.
100 PRINT
101 PRINT
102 PRINT
103 PRINT
104 PRINT
105 PRINT
106 PRINT
107 PRINT
108 PRINT
109 PRINT
110 PRINT
11 Dummy Lines
(or more if the above
program was changed)
SAVEing the program at this stage is advi-
sable.
Now the Loader Program is ready to be
RUN, so enter RUN and NEWLINE.
Enter the decimalised machine code
instructions carefully. The values are
repeated below in the format that appears
on the screen. A CHECKSUM is incor-
porated for convenience. If a code has
been entered wrongly, the correct value
can either be entered directly using a POKE
command, or the whole of the Loader can
be RUN again.
March/April 1981
CHECKSUM = 4033
Once the machine code has been entered
correctly, SAVE the program again. Now
comes the moment of truth! Enter a line
containing USR(16427). e.g. LET
K=USR(16427) and the rectangle should
appear.
If the rectangle does not appear go back
to one of the SAVEd versions and find the
error.
The best form in which to save the routine
is to delete lines 30-90, and to replace line
20 with:
20 REM LINE 10 IS OFF THE SCREEN,
USE LET K=USR(16427) TO DRAW A
RECTANGLE.
So now SAVE the final version.
A Demonstration Program
The following extract from a mixed
BASIC/Machine code Life program for
the ZX80 shows the above routine at
work.
10 REM (prepared as above and held off
the screen)
20 LET A = USR (16427)
30 INPUT A
40IFA 1ORA 300THENGOTO30
50 LET A=PEEK(16396) + PEEK (16397)
*256+34+А +((А-1)/30)*3
60 POKE A, -52*(PEEK(A)=0)
70 GO TO 30
The above program is used to enter |
characters into the required positions. The
program also contains the facility of
removing a character by overwriting the
character with a "space".
I hope that the above article will prove
useful to many readers, and I would certainly
be interested in seeing any programs written
as a direct result of reading this article. Г]
Are you in
SYNC?
If not, you should be. We would like any
programs, translations of existing pro-
grams, games or tips which you have to
pass on to fellow Sinclair 4 Х-80 or Micro-
Ace owners. Articles are much more
lively if accompained by photos (black
and white), diagrams, and illustrations. If
you do not have an output printer, please
type program listings and carefully check
them against the listing on the screen.
Sample runs should be included with pro-
grams rather than just a description of
what the program does. Articles should be
typed, double space. Your name and
address, with phone number should be on
first page; all other pages should be num-
bered. АП submissions should include re-
turn postage. Payment ranges from $15 to
$40 per printed page.
Please send all submissions to:
SYNC
39 E. Hanover Avenue
Morris Plains, New Jersey 07950
The magazine for Sinclair ZX80 users
Cir
1
L
4
P)
©1980 моду таужы-/
JCREPT NE COMPUTING
—
=
a
(
c
T-SHIRTS!
Proclaim the computer of your choice on your
chest with our own Crash Cursor and Sync.
Design is silver on dark blue shirt for a striking
effect. Available in adult S,M,L and XL. $6.00
postpaid in U.S.A.; 3.00 postpaid in U.K. Send
U.S. orders to SYNC, 39 East Hanover Ауе..
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SYNC, 27 Andrew Close, Stoke Golding,
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15
Memory Display
David A. Cromely
The Memory Display Program presents |
16 Bytes of memory in binary, octal, decimal,
and character. You can enter a one-to
four-digit hexadecimal starting address, or
hit NEWLINE, if you want to continue
without a new entry. To end the display
enter Z.
Address E00 (hex) houses the generator
portion of the ROM, the RAM is at address
4000 (hex), and the program begins at
address 4028 (hex). Lines 60 to 90 convert
the hexidecimal address to decimal; lines
110 to 140 call the subroutine to print the
address in hex, and lines 180 to 210 trigger
the subroutine to print the memory contents
in binary, while lines 220 to 240 print in
octal, and lines 250 to 270 in hexidecimal.
Line 280 prints the contents in decimal
with leading zeros, and the character. Lines
310 to 430 convert the decimal number in
X to N digits using radix R, and then prints
the digits. If the radix is 2 (binary) a black
or white square is printed instead of O or 1.
David A. Cromely, 5136 Redmond Road,
. Cheyenne, WY 82001.
LET А 16
INPUT A$ X.
IF @g="Z" THEN LIST ~a
LET A= à + 14 5%
IF АФ = " " THEN GOTO 100 м
) LET А = & 14 + CODE (A$) - 28
LET АФ = TLS (AS)
IF NOT A$ = " " THEN GOTO 70
CLE
LET R = 14
LET М = 4
КЕТ X
GBOSUB (3
FRINT
PRINT
FUR I 9 TO 193
LET К ҒА
LET М =
LET X = PEER (+1)
ЕСІН ZIC
LET К =
LET М =
СС са
осо LET А =
LET М =
GÜSLIBE x
TLE (ZTR$ (X + 10002)5" "s СНК
GOTO 20
LET Y
LET F
FOR 4 =
LET 0
LET Y =
LET F = F,
IF NOT К = z THEN GOTO 400
IF ПІ = 1 THEN LET П = 128
LET U = p - 25
FRINT CHRS ІП + 29):
NEXT .
FRINT из
RETLIRN
CX)
Worth A
Fortune
Past issues of Creative Computing. What
are they worth today? It varies. Toacollec-
tor, Vol. 1, No. 1 is worth $7 ог $8. То a
scrap dealer, less than two cents.
But were not selling old back issues.
Werre all out.
On the other hand, you know that much
of the content of Creative Computing is
timeless. The Depth Charge program in
Vol. 1, No. 1 is just as challenging today as
the day it was written. Walter Koetke's
series of five articles on using computers in
the classrom are as valid today as the day
they first ppeared in print. And scores of
people have written about obtaining re-
prints of Don Pieles classic problem-
solving series.
Our Mistake
In our early growth years when we had
5,000 and then 10,000 subscribers we
couldn't imagine we would ever need more
than 1000 extra copies for back issue sales.
Thats about what we printed extra. How-
ever, by the time we were going into Vol-
ume 3, we found our stocks of Volume 1
issues virtually depleted.
Our Solution
So we selected the best material from
Volume 1, edited it, put it together in book
form and sold it for $8.95, about the same
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Most other magazines in a high tech-
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because we ve concentrated on applica-
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Creative Computing long after they ve dis-
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magazines.
Now you can obtain the best material
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magazine form.
Our Offer
We have a unique special offer, so pay
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Less discount (5% for two items, 10% for
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March/April 1981
SD |
FOUR CLASSIC COMPUTER GAMES FOR
THE MICROACE AND 4-K ROM ZX80.
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17
Truth In Programming
It's time for a little truth in programming,
time for a bit of logic. Why let your programs
slave away with boring numbers when they
can deal with such fascinating concepts as
truth and falsity? The logical capabilities
of the Sinclair represent one of the best
ways to shorten and speed up programs.
Many programers don't make full use of
these Boolean operators, mainly because,
while they are not difficult to use, they are
different from other parts of Basic. Boolean
logic uses operators such as "AND" and
"OR." The major ways to use these operators
will be discussed below.
Logical operators deal with the concepts
"true" and "false". In the Sinclair, true is
represented as -1, false is represented as 0.
This is just a convention; some machines
use 1 for true, some use 0 for true and 1 for
false. Knowing how the Sinclair represents
true and false, the next question is, what
makes something true or false? In Basic.
any expression or variable with a value of
0 is false, any other value is considered
true.
There are many ways to use logical
operators. Let's start with a simple example.
Take the statement 10IF X > ООВХ < 0
THEN GO TO 50. This could be replaced
with 10 IF NOT X — 0 THEN GO TO 50.
But there is an even shorter way to perform
the operation. We want to take the branch
whenever X is not equal to 0. And, if X is
not equal to zero, X is considered to be
true. Using this, we can perform the function
with the following line: 10IF X THEN GO
TO 50. The IF... THEN statement makes
the branch only when the IF part is true. If
18
David Lubar
(LET X=Y=Z=W)
X is not equal to 0, X is true, so the branch
will be taken. Only when X is zero will the
branch not be taken. Conversely, the
statement 10 IF X = 0 THEN GO TO 50
can be replaced with 10 IF NOT X THEN
GO TO 50. You can use this technique to
check against numbers other than zero by
changing the variable to an expression.
For example, IF NOT X = 15 THEN GO
TO 100 is equivalent to IF X - 15 THEN
GO TO 100. When X is not equal to 15,
the expression X - 15 will evaluate as true,
and the branch will be taken. What the
above example boils down to is this: the
IF...THEN statement can be used with
any logical operation.
Another important aspect of logical
operators is their ability to provide a value
that can be used to advantage in a program.
Remember that true is represented as -1
and false is represented as 0. Take the
following programming problem: a player
has to guess whether a number is odd or
even. The program must determine whether
the guess is correct. The first step would
be to get the guess. This could be done
with:
10 PRINT "ODD OR EVEN?"
20 INPUT G$
Now, some way has to be used to compare
the guess with the number. This brings up
another problem: what is the simplest way
to determine whether a number is odd or
even? In integer arithmetic, an easy way is
provided by the fact that division rounds
off a number to the integer remainder.
The result of dividing 7 by 2 would be 3.
This gives a way to determine whether the
number is odd or even. For any integer N,
if N/2 — N- N/2, then the number is even.
Try this with an odd number, then with an
even one. N/2 will only be equal to N - N/2
when N is even. Now we could use lines
such as 30 IF N/2 — N- N/2 AND G$ —
"EVEN" THEN GO TO 100, where line
100 handles a correct guess. But the full
comparison of guesses in this manner seems
somewhat long and inelegant. Instead, we
can take advantage of the values given to
logical operations. It happens that the
CODE for E is 42 and the CODE for O is
52. If we can find an expression that
produces a value of 42 when the number is
even, and 52 when the number is odd, we
can compare this value with CODE (G$)
to determine whether the guess is correct.
This can be done using the fact that (N/2
— N- N/2)is true when N is even and false
when N is odd. Since true gives a value of
-1 and false a value of 0, the comparison
can be done with the following line:
30 IF CODE (G$) = 52 (N/2 = N - N/2) *
10 THEN GO TO 100
Since even numbers will cause the expres-
sion in the parentheses to be evaluated as -
1, the result will be 52-1* 10 thus matching
the CODE for E. If the number is odd, the
result will be 52 +0* 10, matching the
CODE for O.
This concept bears repeating: airthmet-
ical operators can be used to return logical
values. АП in all. a very valuable technique.
It can be used to adjust scores in games or
alter results depending on answers. Since
false returns a value of 0, and multiplying
any number by zero results in zero, when
SYNC Magazine
you add a logical expression multiplied by
a constant to a number, the number only
changes if the expression is true.
The equal sign can also be used more
than once in a line. This fact caused a bit
of confusion when mentioned in the ad for
SYNC magazine, and deserves a fuller
explanation. LET X — Y — Z is a valid
expression, but does not assign to both X
and Y the value of Z. These variables
must be defined first. (To take an analogous
case, LET X = X 1 is valid, but will cause
an error if X hasn't been defined.) What
the expression does is compare Y to Z and
give X the logical value of this comparison.
If Y equals Z, X will be assigned the value
of -1. This fact can be exploited when a
program requires several IF... THEN state-
ments that all use the same comparison.
For example:
10 IF Y = Z THEN LET T=T +1
20 IF Y = Z THEN PRINT “YOU ARE
RIGHT”
Assume that several more uses of this
comparison are made later. These can be
replaced with:
10LETX=Y=Z
20 IS X THEN LET T = T + 1
30 IF X THEN PRINT “YOU ARE
RIGHT”
In the above example, no space was saved.
But if the program makes repeated use of
the comparison, this trick will save space
since the expression IF X is shorter than
the expression IF Y = Z. Also, the shorter
version will execute more quickly since it
has less to perform.
While arithmetical operators can be used
to produce logical values, there are also
certain functions that are used specifically
for logical operations, namely AND, OR,
and NOT. AND is considered true only
when all expressions linked by it are true.
OR is true if at least one of the expresions
linked by it is true. So the statement IF X
AND Y AND Z THEN GO TO 100 will
take the branch only if all three variables
have a value other than zero. If any one of
the variables is zero, the expression will be
false. Again, the value produced by this
expression can be used in arithmetical
operations. The statement LET A = (X
AND Y AND Z) * 10 will give A the value -
10 if X, Y, and Z are all true. If any of the
three are false, A will have a value of 0.
These operators can be combined,
producing lines such as IF NOT (A AND
B) OR C THEN GO TO 100. While such
expressions seem complex at first glance,
they become simple when evaluated in
sections. The first step would be to look at
anything in parenthhses. A AND B by
itself is simple. As stated before. this
expression is true only if both A and B are
true. NOT (A AND B) has the opposite
value of (А AND B). 50, if (A AND В) is
false, NOT (A AND B) will be true. Now,
the entire expression can be understood.
It is true if either NOT(A AND B) is true
or if C is true. To test your understanding
of this, determine, before looking at the
next paragraph, what logical values of the
he
Son
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SOC
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OL (34
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m 7NEW PROGRAMS e Mastermind e Hangman
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ME eSpace-Docking ®ShareValuation™
Tant ePutting e Plus Others
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PLUS HINTS AND . eProgramWriting eCassetteUse
TIPS ON e Graphics e Program Efficiency
21 PLUS REFERENCE eBasic 128 Pages
SECTIONS ON ® 2Х80 Op Codes
7 - eError Codes © ГА e a 5
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Add $2.00 for air mail freight and shipping.
Master Charge credit cards accepted.
PHIPPS ASSOCIATES з. DOWNS AVENUE, EPSOM, SURREY, ENGLAND. WEN
or Telephone Epsom (03727) 21215 Quoting your Access Card Reference. No callers please.
POCKET BOOK
Subroutines
variables would make the expression
false.
Since the major connective in the expres-
sion is an OR, the expression will be false
only when both sides of the OR are false.
So C has to be false. NOT (A AND B) must
also be false. NOT (A AND В) is fale when
(A and B) is true. (A and B) is only true
when both A and B are true. So, when A is
true, B is true, and C is false, the expression
will be false. With any other values, it will
be true. |
Logical operations make an excellent
addition to a programmer's bag of tricks.
They can be used to shorten programs,
speed up programs, and to perform things
that would otherwise require great
difficulty. o
Including Postage & VAT
Cassette Tape of
Programs above
plus book. £14.95
кесте
DATA Statement Simulation
One of the most noticeable short-
comings of the Z X80 Basic is that there
are no DATA statements.
With numbers it is possible to simulate
the DATA, READ and RESTORE
instructions by a simple program.
This can be done using a REM state-
ment. The numbers are placed in a list
within the REM statement, as is done
with DATA statements, separating each
number by a comma, and ending the list
with a comma.
The DATA is then read by PEEKing
the number out of the REM statement
and placing it in a variable, as demon-
strated in Demo 1.
R. Turner, 396 James Reckitt Avenue, Hull, N.
Humberside, HU8 ОЛА, England.
10 REM 12. 08. -2145,
11 LET D = 9
iS LET C = 0
14 LET E =
20 GÜSUB 100
22 IF D= 1
ӘЗ LET пе Ó
z5 LET E = А + E + 1
30 PRINT C
40 LET C = 0
во — INPLUT A$
70 вата 20
cO УГЕ"
100 FOR à = О TO 100
LLO LET B = РЕЕК(Е + А) ~
120 ТЕ B = 188
125 IF В = ФО THEN STOF
126 IF NOT В = 192 THEN GOTO 120
іре LET O = 1
127 GOTO 140
130 LET C = C # 10 + R
Do not use variable A, B, C, D, OR E
elsewhere in the program.
Variables
A —Dummy in FOR/NEXT loops
B—Number read from REM statement
should be PEEKing
C— Number read from DATA statement
D —Sign Flag + (0) - (1)
E— Pointer to next number on DATA list
20
THEN RETURN
Richard Turner
In this case the number is put into
variable C. This may then be put into any
other variable by using a LET statement
such as:
LET А(2) = C
E stores the pointer to the next item of
DATA and in this case the start of
DATA is at memory location 16427.
LET E — 16427
this will act as the RESTORE statement.
The DATA can be placed anywhere in
a program, but the memory location of
the start of the data must be found.
The following program finds all the
REM statements in a program and prints
the memory location where the data will
start. Type this in at the end of a program
and then erase it after it is used. []
DATA STATEMENT
FLAG FON + UR - NL.
NO. READ FROM LATA
BEGINNING OF HATA
EXTRACT FIRST NUMER
{) ? = 1 3
THEN LET C = -Ë [3 D SET? IF 50 CHANGE SIGN
RESET FLAG
PUINTER TO NEAT Ми,
No. FROM DATA
ПМ DATA
РКЕ NEWLINE іш EATRALT NEAT NUMBER
Bere trm
CHECK FOR COMMA
CHECK FOR END Gr LINE
CHECK FOR MINUS SIGN
SET FLAG
SOOO
JOLO
LET A = ҒРЕЕК(163У2) +
FUR He 16424 TU à
голо TF FEEEKCBO = 254 THEN FRINT В
S030 NEXT В
The use of this simulation means that one
of the faults of the ZX80 Basic may be easily rectified.
PEER ILOJ
EUM) # UA
* 1
SYNC Magazine
EM
A one-hour LP record of eight synthesizers may
change your views about computer music forever
Binary Beatles
by David Ahl
Computer music. Who needs it? It's mostly
boring beep, beep, beeps or wildly modern
stuff. It's certainly nothing you'd want to
listen to more than once. That's what | thought
about computer music and most of my friends
agreed.
In 1978 | entered Yankee Doodle Dandy
into my Software Technology system just
to be different. Dick Moberg heard of itand
asked me to perform in the Philadelphia
Computer Music Festival. | agreed expecting
to be the only one with something out of
the ordinary. | was wrong.
Computer Accompanist
Nine individuals and groups performed
in the festival. There were the usual Bach
pieces but even they were different. Gooitzen
van der Wal performed the last movement
of the 2nd Bach Suite in a unique way. He
played the flute solo while using the computer
as accompaniment.
Then Dorothy Siegel did the same thing,
playing the clarinet solo part of Wanhal's
Sonata in b flat. The audience went wild.
Hal Chamberlin played Bach's Tocatta
and Fugue in d minor. Butalso with a differ-
ence. He used a large computer before
hand to "compute" the waveform of every
instrument playing every note. It took one
hour of computation time for each two min-
utes of playback time. The result could hardly
be distinguished from the organ in the
Hapsburg Cathedral.
Don Schertz had a home brewed synthe-
sizer truly mounted on a breadboard that
allowed him to control 25 parameters of
each note. It produced spectacular sounds
in his arrangement of Red Wing.
Singing Computer
In 1962, D.H. Van Lenten at Bell Labora-
tories produced the first talking computer.
Bell engineers taught it to recite the soliloquy
from Hamlet. Then they went one step further
and taught it to sing Daisy both alone and
accompanied by another computer. This
was also performed at the festival.
Yes, the Beatles were represented. Andrew
Molda played Hey Jude on his COSMAC
VIP system with a program called PIN-8
(Play it Now).
Superb Quality Recording
All these pieces and twelve others were
recorded with broadcast quality equipment.
Because of audience noise, eight were re-
recorded later in a studio. We then took
these tapes to Tru-Tone, a top recording
KNOW YOUR ZX80
With LINSAC products for the Sinclair ZX80
THE ZX80 COMPANION
(Second Edition)
Maunder, Logan and Trotter
THE ZX80
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The ZX80 Monitor A complete assembly language listing of the ZX80's 4К Monitor,
with annotations — Price £10.00 incl. UK postage.
Cassette Software
All LINSAC program packs are on single C12 cassettes with printed run instructions. All run on 1K ZX80's unless otherwise
stated. Price £10.00 per pack incl. UK postage.
ISBN 0 907211 00 3. Price £7.95 incl. UK
This best-selling manual on the Sinclair ZX80
covers ZX80 BASIC, hardware and programs
and has a detailed explanation of the ZX80
Monitor, routines and entry points. A routine
for generating moving displays is also included.
Ch.1 — Operating the ZX80.
Ch.2 — Theory of Computers
Ch.3 — ZX80 BASIC
Ch.4 — The ZX80 Monitor
Ch.5 — Construction and Hardware
Ch.6 — ZX80 Programs
App.1 — Comparison of Z-80 Opcodes and
ZX80 Characters.
App.2 — The 8K ROM.
For a cassette of ten programs from the Com-
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studio and cut a lacquer master. It was a
long session since the recording engineers .
insisted upon analyzing the sound from every
source and setting up the equilization curves
accordingly. It took over 12 hours to produce
a one-hour lacquer master.
Finished recordings were then pressed
on top-quality vinyl and inserted into liners
and record jackets. These were then shrink
wrapped in plastic for maximum protection.
We guaranteee that every LP record is free
from defects or we will replace it free of
charge.
The extensive descriptions of each of the
eight synthesizers and the festival would
not all fit on the jacket so we ve included an
extra sheet with each record. This entire
package is mailed ina protective corrugated
package to insure that it reaches you in
mint condition. The cost is a modest $6.00
postpaid in the U.S. and $7.00 foreign. Send
order with payment or Visa, MasterCard or
American Express number to Creative Com-
puting, Morris Plains, NJ 07950.
This LP record contains one hour of eight
computer music synthesizers that you'll listen
to over and over again. Send in your order
today at no risk whatsoever.
creative
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Morris Plains, NJ 07950
Toll-free 800-631-8112
(In NJ 201-540-0445)
NOW AVAILABLE
ke
GAMES PACK 1 — Three Towers, Number Guessing, Mastermind, Sketcher, Hurkle, Nim, Symbol Simon.
GAMES PACK 2
GAMES PACK 3 (2K*) — Fruit Machine, Four-in-a-line, Zombies
EDUCATION PACK 2
EDUCATION PACK 3
UTILITY PACK 1
(2K*) — CAL Quiz Package with three sample data sets.
Nine Lives, The Maze Game, Plain Sailing, OXO, Chinese Puzzle, Tower of Hanoi, Battleships.
EDUCATION PACK 1 — Maths Drill, Dot Recognition, Musical Notes, Spelling Quiz, Day Finder.
Graph Plotter, Prime Factors, Number Bases, Bar Charts, Statistics.
Memory Display, Hex Code Monitor, Renumber, Memory Search.
LINSAC
68 Barker Road, Linthorpe,
Middlesbrough, Co. Cleveland TS5 5ES
March/April 1981
board .
conversions
Standard Compute
minutes
inversion with reverse video
Keyboard with complete parts and plans $65.00
Wired keyboard, complete with plans $85.00
а nS SEE RNS ЗЕНА ЕЕ ЖЕ S О ы м о Е
Mail for information:
L.J. H. Enterprises
P.O. Box 6273, Orange, CA 92667
21
Is it possible for a game to present an
interesting challenge, yet fit in 1K of RAM?
As evidence that the answer is "yes," I
offer Widget, a relative of the games
Hammurabi and Lemonade Stand, in which
the player allocates his resources for the
best effect. As the player, you are the
head of the United Widget Company, trying
to expand your business as rapidly as
possible without going broke.
You start out with one plant and $90,000.
A plant is capable of producing as many as
1000 widgets a month, which will sell for
$10 each. The monthly fixed overhead is
$4000, including the mortgage cost for
your first plant. In addition, it costs $5 per
widget to produce any widgets in excess of
the first hundred. To sell any widgets, you
have to advertise. Naturally, the return on
advertising isn't entirely predictable, but
you have to learn how much to spend in
order to sell what you produce аға profit.
The key to making money is buying
more plants. A plant costs $100,000 to buy
and $2000 a month to maintain, and it lets
you produce another thousand widgets a
22
cet
Gary McGath.
ACME- *
WIDGETS inc.
Some of the many versions of Widget as 4
illustrated bv Timothy Truman.
| у, A UT
month. This means more fixed cost and
more need for advertising; it also means
economies of scale. You'll notice that as
production increases, it takes more adver-
tising dollars to sell each widget. On the
other hand, if you keep a steady flow coming
out of your plants, each month's sales will
produce a carry-over effect into the next
month.
With these costs in mind, you can start
playing Widget. Each turn represents one
month. At the start of the turn, the screen
shows your current cash balance, number
of plants, and inventory. If you have at
least $100.000, you are asked, "Buy a plant?"
To buy a plant, answer “У” (just the one
letter); anything else means "no."
Next (or first, if you had less than
$100,000). the program asks for your ad
budget. Enter the number of thousands of
dollars that you want to spend on ads; for
example, to spend $4000, enter “4.” You
will be asked again for input if you try to
spend more than you have.
Finally you are asked how many widgets
you want to produce. Enter the number of
hundreds of widgets you want to produce,
remembering that each plant can only
produce 1000 widgets. Again, the program
wont let you go until you've entered а
legal number.
The advertising cost is then subtracted
from your cash balance, sales are deter-
mined, revenue comes in, and then the
other costs are subtracted. If you can't
meet your costs, the message "You are
bankrupt" appears, and the game is over.
Otherwise, the program goes on to the
next month.
Before starting, decide how many months
you're going to play. Sixty turns (5 years)
or 120 turns (10 years) make a good game.
Keep score by calculating your company's
net worth, which is its cash balance plus
$100,000 per plant. There isn’t any prede-
termined winning score, but the outcome
of a fairly well-played game would be to
have 5 plants and $50,000 or more at the
end of 10 years. []
Gary McGath, 5 Ames Rd., RFD #3, Milford, NH
03055.
SYNC Magazine
Zu s «t ]
= RANLDCGMIZE
6 LET Z = 1
10 LET F = 1
20 LET M = 770
О LET I = 0
40 LET $ = 10
joo CLS
110 PRINT "MONTH" „7
120 LET Z = Z + 1
300 PRINT "YOU HAVE" , "$" :M; "OO"
310 PRINT F3" PLANTS"
320 PRINT »15 "00 WIDGETS"
330 PRINT "LAST MONTH You
SOLO "sm; "oo"
250 IF M x 1000 THEN ба та 410
360 PRINT "BUY А PLANT?"
370 INFLT YS
250 IF NOT Y$ = "Y" THEN GO Та 410
390 LET Р = Р + 1
400 LET М = M - 1000
410 РКІМТ "АП BUDGET IN 10005 7?"
420 INPUT В
430 IF B * 10 > M THEN GO та 420
440 LET М = М ~ B * 10
450 FRINT "PRODUCTION IN 1005 7"
470 INFUT W
430 IF W > 10 * Е THEN GO To 470
470 LET I = I + W
200 LET & = $ / (RNE (3) + 3)
210 IF B = 6 THEN GO та 550
ЭРО LETS = Б + (В - 6) * 5
"30 LET В = 6
SAO IF В < Т THEN GO TO 400
S60 LET $5 = 5 + (В - 2) # 7
70 LET B= 2
4200 LET 5 = 5 + БВ * B
4140 IF С > I THEN LET 5 = I
420 LET М = М +5 # 10
630 ЕТІ = I-$S
640 LET М = М ~ zo * P — zo
450 LET M =M- (W - 1) * &
640 IF NOT M О THEN ба TO 100
зоо PRINT "YOU ARE BANKRUPT. "
MONTH 1
УГ! HAVE $70000
1 FLANTS
ООО WIDGETS
LAST MONTH YOu SOL TI 1000
АП BUDGET ІМ 109057
MONTH 29
YOU HAVE 101000
1 PLANTS
000 WIDGETS
LAST MONTH YOU SOLD 1500
BUY A PLANT?
MONTH 61
УГ HAVE $71000
2 FLANTS
200 WIDGETS
LAST MONTH YOu SOLE 1900
AD BUDGET IN 10005?
MONTH au
УП HAVE $0000
3 FLANTS
ооо WIDGETS
LAST MONTH YOU SOLD 2600
АП BUDGET IN 10005?
MONTH 121
УГ
LAST
BUDGET IN 1000027
AL
HAVE $53000
к FLANTS
400 WIDGETS
MONTH YOu SOLD Shoo
March/April 1981
OULMLITY SOF TMLRE
Graphics ў
( #5 ) Poke to memory mapped screen - use your ZX80 as а
Sketching pad. Character and direction control.
Music
( #15 ) Tunes to your cassette recorder, with selectable
octaves, semitones and duration from a wide range
of notes. Your tune will repeat itself continuously.
For the best results, memory 1K is necessary.
Po QUT ЖЕНЕ)
( £5) Hex. Loader - this routine provides а simple means
for machine code programming in Hexadecimal notation.
А 'String Rotate' demonstration program is included.
Hex. Display - this routine allows you to inspect
the contents of memory in 64 byte blocks - just
enter the decimal address.
е Display ;
( $20 ) Write your own games or use the ZX80 for continuous
data monitoring. You decide how long a dísplay will
hold before your program continues (1/60th second to
approx. 16 mins.). A Hex. Loader and а 'top row'
keyboard scanning routine is included with a demo.
Жалбыр;
( $20 ) Try your skill at knocking all the bricks from the
wall before your final ball is lost. The ball starts
at '9' and decrements each time it is lost until the
game is over. The paddle moves swiftly under your
control - the game restarts automatically.
Movies
( #15 ) Pictures of your own creation (7x8 characters) are
displayed in rapid rotation giving animation effect.
For the best results, memory 1K is necessary.
әсе E йыз
( #25 ) A simplified version of the famous arcade game.
Zap the intruders as they attempt to land. The impulse
to beat your last score is paramount. Requires 2K memory.
No modifications to hardware whatsoever. All software is thoroughly
tested and claimed to be the most advanced developed so far.
Games are written in machine code to make maximum use of memory and
provide continuous live action without loss of T.V. synchronisation.
All programs run in 1K memory unless stated otherwise.
Inclusive prices for program listing, details and Air Mail postage,
(Send only $90 total if all the software listed is ordered together).
Cheques (or S.A.E. for U.K. price list and details) to:- K.Macdonald,
26 Spiers Close, Knowle, Solihull, West Midlands, B93 9ES, ENGLAND.
Rose Cassettes
R.F. SHIELD
(Cuts down T. V.
interference)!
TUITION for your under 13 year old child. Make itfun
to learn Maths., English, General Knowledge and
Reasoning. 4K ZX80 — Cassette $10.80. Also
GAMES cassettes (4K) $10.80 and (1K) $4.80.
Mailing and packing $1.80. Check to ROSE
CASSETTES,148 Widney Lane, Solihull, West
Midlands B91 3LH. England.
WYNCOM
WYNDHAM COMPUTER SERVICES
Languages, History, mathematics:
WYNCOM's TUTOR program stores
questions on any subject, presents
them in random sequence. 1K ver-
sion displays answer, 2K checks
student’s response. Listing 1K $7
(£3), 2K $12 (£5) from WYNCOM,
11 Furze Platt Road, Maidenhead
SL6 7ND, England.
Kit for the ZX-80 ог Micro-Ace. Send
$5.00 U.S.A. To:
Outbound Engineering
P.O. Box 218
Chandler, Texas 75758
U.S.A.
Why wait 2 or 3 weeks for your check
to clear? Send Cash. Texas residents
add 595 Sales Tax.
23
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In Artillery the player fires a cannon at a
stationary target. The screen displays the
gun location, the target site, and the
approximate range. To take aim the cannon-
eer selects the angle at which the cannon
is raised, between 0 and 90 degrees. The
display then indicates whether the shot
was long, short, or on target.
With a maximum range of just over
200,000 yards — the display gives a relative
range within approximately 10,000 yards.
C.R. Whetstone, 211 Clarendon Ave., Baltimore,
MD 21208.
March/April 1981
юж ^h m "in f^ m mz
b-4 -4 м
ЕТ A=RNDC2030)
290
ІМ 55212
1 TD 20
T 554221
XT à
Y SCA/100)
T SCL/100)
INT X;
R €=1 T2 20
S€Q)=1 THEN
5С642:2 THEN
SCQ223 THEN
та
NT "M/R"
URN
NT "TARGET RANS
NT
508 140
МТ
NT "INPUT GUN
UT N
М<0
N»45
©
29
£5
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NT "RANGE =";
NT
593 150
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2000
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27
Game of Life
pe нн C —————— á— —— ead
el
p
Generally, a mathematical model is a
representation of some real-life process,
expressed in mathematical form (such as
a set of related equations) or in algorithmic
form (such as a computer program). Usually
the model is by necessity a simplification
of the actual process, since real-life pro-
cesses tend to be highly complex. One
advantage of embodying the model as a
computer program is that we can run the
program and thus simulate the process
being modelled. By varying certain features
of the program, we can learn something
about the relationships between the compo-
nenets and the overall structure of the
process. In addition, if the output does
(1) World — Cells live on an infinite
two-dimensional plane of squares (like an
infinite checker-board, except that all
squares are identical).
not sufficiently coincide with observed
reality, the model can be revised and
improved.
It is also possible to model a purely
abstract process. We don't often see this
done. After all, if someone asked you to
describe some abstract process, what would
you say? However, many games start out
as purely abstract processes. For example,
tic-tac-toe or checkers are abstract from
the point of view that they represent no
real-life process. Occasionally, it turns out
that an abstract process represents a real-
life process either by accident or design.
The following game is one such example
which in some ways represents life itself.
(2) Neighborhood — Each square has
eight neighbor squares. In the diagram
below, the neighbor squares for the square
with the asterisk (*) have been colored in.
The game of Life was devised by John
Conway, a mathematician at the University
of Cambridge, and made popular by a
series of articles written by Martin Gardner
in recent issues of Scientific American.
Ever since the first article appeared in
October 1970, hundreds of mathematicians
throughout the world have become fasci-
nated with the model and have been
exploring its properties.
The game consists of following the
successive generations of a particular
imaginary type of cellular life-form. The
life processes of these cells are represented
by the following mathematical model,
(3) Survival — A cell (always represented
by a *) which is living in generatin n, will
remain living in generation n+1 if and
only if it has exactly two or three living
neighbors in generation n.
(4) Death — However, in all other cases
the cell dies. Specifically: If it has one or
no neighbors it dies from isolation. If it
has four, more than three neighbors, it
dies from overpopulation.
(5) Birth — If a square is empty during
generation n, a living cell will be born
into that square during generation n t 1 if
and only if that square had exactly three
living neighbors during generation n.
The only trick is to remember that all
survivals, deaths, and births occur simul-
taneously, and so the simplest way to
keep the bookkeeping straight is to have
two separate copies of the world — one
for the old generation and one for the
new one you are forming. For each square
in the old world, decide what its state will
be next time, and mark this down in the
corresponding square in the new world.
SYNC Magazine
which captures several properties common
to all life-forms.
The game is played simply by picking
some initial starting pattern and watching
the development of some very interesting,
and often beautiful patterns of symmetry.
However, the player must be extremely
careful because mistakes are easy to
make.
As an example, we will trace three
generations of the following initial pattern
(we have numbered some rows and
columns for reference purposes only):
Following the rules of our model:
No births will occur in squares 1, 2, 3, 4,
or 5 because none has three living neigh-
bors.
The cell in square 6 will survive because
it has two living neighbors (10 and 11).
A birth occurs in square 7 because there
are three living neighbors (6, 10, and 11).
No birth occurs in squares 8 or 9.
The cell in square 10 survives because it
has three living neighbors (6, 10, and 15).
The cell in square 11 survives also because
it has three living neighbors (6, 10, and
15).
No birth occurs in squares 12 or 13.
A birth occurs in square 14 because there
are three living neighbors (10, 11, and
15).
The cell in square 15 survives because it
has two living neighbors (10 and 11).
No birth occurs in square 16 because it
only has two living neighbors.
During this process, we have been filling
in a picture of G1, and the end result is:
FOO
joo DIM A (63)
110 FOR I = 1 TO 4&3
120 LET ACI) = 128 # (КМО (2) - 1)
1:0 NEXT I
200 FOR L = 0 TO &
210 FOR J = 1 To 7
220 LET IT = J + 7 #L
2530 FRINT CHR$ (ACT) )3 The following program for the game of
240 NEXT 4 Life is from The Melbourne House book,
250 FRINT Thirty Programs for The Sinclair 2 Х-80
260 NEXT L IK.
270 PRINT "PRESS 1”
шо INFUT А
270 CLS
300 Е N R I= 70 55
210 LET X = О
azO IF ((I + 1) АМП 7) = О THEN са TO 230
S30 LET X = (ACI + 1) > 127)
340 IF ((І - 1) АМП 7) = о THEN GO TO 340
220 LET X = X + (ACI ~ 1) „> 127)
360 FOR d 7 TO F
370 FOR К = — 1 TU 1
зао IF R = О THEN GO TO 420
290 LET Е = I + К * Jd
400 IF (к АМП 7) = Q THEN GO TO 420
410 LET X = X + (ACK) 2127)
420 NEXT К
4x0 NEXT 41
440 LET ACI) = ACI) - X
460 NEXT I
470 IF ACI) = 3 OR ACI) = 130 OR ACI? = 131 THEN GO TU
420 LET ACI) = O
470 GO Та 510
200 LET ACI) = 128
10 NEXT I
220 GO TO #900
March/April 1981
29
Life, continued...
Experiment 1
Using pencil and paper, carefully com-
pute G2, the next generation for this
same society of cells. If you do it cor-
rectly, you will find that G2 is the pattern
which Conway calls the “Беешуе”:
Experiment 2
Now compute G3. If you are again
careful, you will discover that G3 is iden-
tical to G2. Why does Conway call the
beehive a “still-life”? If you are not sure,
think about G4, G5, бб...
Experiment 3
Using pencil and paper, compute GO,
G1, G2 and G3 for the initial pattern
below:
If you do it correctly, G3 should look
familiar to you.
Experiment 4
By now you've no doubt noticed that
with pencil and paper, this game is an
extremely slow process, and mistakes are
all too common. If we ever hope to look
at more than a few patterns, we're going
to have to turn to the computer for help.
Write a computer program which
simulates "Life" for any given initial pat-
tern, and which has the following
features:
(1) Allow for as large a world size as your
particular computer facility will permit
(obviously an infinite plane is not pos-
sible in a finite memory). You will prob-
ably want to use array structures with
two subscripts (row and column).
30
(2) Whatever world-size you are limited
to, make sure your program doesn't try to
alllow births outside your world, even
though properly these would occur on an
infinite plane.
(3) Make sure your algorithm allows all
survivals, deaths, and births during a
given generation to occur simulta-
neously, as discussed above.
(4) Allow the user to input the initial
pattern in a convenient format, such as
pairs of (row, column) coordinates.
(5) Make your program efficient and
your output as close to the format of the
pictures above as possible.
Once your algorithm is designed, and
your program is written, debug your pro-
gram by running it on the following initial
GO pattern, and carefully check your
output vs. the results below:
Warning !
Depending upon the world-size you are
limited to, certain "large" patterns may
grow differently than they would on an
infinite plane.
If the society of cells above, however,
fits inside your world-size, you will notice
an interesting cyclic pattern beginning at
GO, which Conway calls “traffic lights".
Experiment 5
When your program is thoroughly de-
bugged and operational, or using the
LIFE program with this article, the real
fun comes in thinking up initial patterns
and watching them grow. Interesting
situations to watch for are:
(1) Other “still-life societies (like the
"bee-hive")
(2 Other "cyclic" societies (like the
"traffic lights")
(3) A society which lives for an extended
period of time without dying, becoming
still, or cycling
Experiment 6
Find copies of the October 1970 and/
or February 1971 issues of Scientific
American and read Gardner’s articles on
"Life." You may want to run your pro-
gram on some of the societies he de-
scribes, such as: diagonal chains, the R
pentomino, the Latin cross, the cheshire
cat, and many others.
Experiment 7
Try to think up changes in the model
(and your computer program) which will
drastically alter the life patterns of the
cells, i.e. by modifying the rules for birth
or death or both. Based upon your ex-
perience so far, try to come up with sets
of rules which will lead to more populous
societies, or more sparse societies, ог
societies which are less symmetric than
those of "Life", etc. The range of possi-
bilities is very large.
Experiment 8
Make some major modifications in
your computer program to make it more
general, by allowing the user to specify
the particular model he wants to investi-
gate. For example, you might have your
program begin by posing the following
questions to the user:
How many neighbors for survival?
How many neighbors for birth?
Then, if the user answered 2, 3 for the
first question and 3 for the second, your
program would follow the rules of "Life."
But if he gave other answers, the program
would simulate for him some other model
he wants to investigate.
Experiment 9
Is there any way you can streamline
your program or the published one so
that you can enlarge the size of the world
it currently handles?
Experiment 10
How might you alter the general con-
cept of "neighborhood" so that entirely
different models could be tested? How
would your computer program have to be
changed in order to simulate these new
models?
SYNC Magazine
The story behind the two best selling
computer games books in the world.
Computer
Games
by David H. Ahl
Everybody likes games. Children like tic
tac toe. Gamblers like blackjack. Trekkies
like Star Trek. Almost everyone hasa favor-
ite game or two.
It Started in 1971
Ten years ago when | was at Digital
Equipment Corp. (DEC), we wanted a pain-
less way to show reluctant educators that
computers weren't scary or difficult to use.
Games and simulations seemed like a good
method.
So | put out a call to all our customers to
send us their best computer games. The
response was overwhelming. | got 21 ver-
sions of blackjack, 15 of nim and 12 of
battleship.
From this enormous outpouring | se-
lected the 90 best games and added 1 1 that
| had written myself for a total of 101. |
edited these into a book called 101 Basic
Computer Games which was published by
DEC. It still is.
When I left DEC in 1974 | asked for the
rights to print the book independently.
They agreed as long as the name was
changed.
г--л---------------------------------ӘНҺмНӘӘЭӘӘӘ-- UU
Contents of Basic Computer Games (right)
Introduction Hi-Lo
The Basic Language High І-О
Conversion to Other Hockey
and More Basic Computer Games (below).
Artillery-3 Life Expectancy
Baccarat Lissajous
Bible Quiz Magic Square
Big 6 Man-Eating Rabbit
Binary Maneuvers
Blackbox Mastermind
Bobstones Masterbagels
Bocce Matpuzzle
Boga Il Maze
Bumbrun Millionaire
Bridge-It Minotaur
Camel Motorcycle Jump
Chase Nomad
Chuck-A-Luck Not One
Close Encounters Obstacle
Column Octrix
Concentration Pasart
Condot Pasart 2
Convoy Pinball
Corral Rabbit Chase
Countdown Roadrace
Cup Rotate
Dealer's Choice Safe
Deepspace Scales
Defuse Schmoo
Dodgem Seabattle
Doors Seawar
Drag Shoot
Dr.Z Smash
Eliza Strike 9
Father Tennis
Flip Tickertape
Four In A Row TV Plot
Geowar Twonky
Grand Prix Two-to-Ten
Guess-lt UFO
ICBM Under & Over
Inkblot Van Gam
Joust Warfish
Jumping Balls Word Search Puzzle
Keno Wumpus 1
L Game Wumpus 2
March/April 1981
Basics Horserace
Acey Ducey Hurkle
Amazing Kinema
Animal King
Awari Letter
Bagels Life
Banner Life For Two
Basketball Literature Quiz
Batnum Love
Battle Lunar LEM Rocket
Blackjack Master Mind
Bombardment Math Dice
Bombs Away Mugwump
Bounce Name
Bowling Nicomachus
Boxing Nim
Bug Number
Bullfight One Check
Bullseye Orbit
Bunny Pizza
Buzzword Poetry
Calendar Poker
Change Queen
Checkers Reverse
Chemist Rock, Scissors, Paper
Chief Roulette
Chomp Russian Roulette
Civil War Salvo
Combat Sine Wave
Craps Slalom
Cube Slots
Depth Charge Splat
Diamond Stars
Dice Stock Market
Digits Super Star Trek
Even Wins Synonym
Flip Flop Target
Football 3-D Plot
Fur Trader 3-D Tic-Tac-Toe
Golf Tic Tac toe
Gomoko Tower
Guess Train
Gunner Trap
Hammurabi 23 Matches
Hangman War
Hello Weekday
Hexapawn Word
Converted to Microsoft Basic
The games in the original book were in
many different dialects of Basic. So Steve
North and | converted all the games to
standard Microsoft Basic, expanded the
descriptions and published the book under
the new name Basic Computer Games.
Over the next three years, people sent in
improved versions of many of the games
along with scores of new ones. So in 1979,
we totally revised and corrected Basic
Computer Games and published a com-
pletely new companion volume of 84 ad-
ditional games called More Basic Com-
puter Games. This edition is available in
both Microsoft Basic and TRS-80 Basic for
owners of the TRS-80 computer.
Today Basic Computer Games is in its
fifth printing and More Basic Computer
Games is in its second. Combined sales are
over one half million copies making them
the best selling pair of books in recrea-
tional computing by a wide margin. There
are many imitators, butall offer a fraction of
the number of games and cost far more.
The games in these books include classic
board games like checkers. They include
challenging simulation games like Camel
(get across the desert on your camel) and
Super Star Trek. There are number games
like Guess My Number, Stars and Battle of
Numbers. You'll find gambling games like
blackjack, keno, and poker. All told there
are 185 different games in these two
books.
Whether you're just getting started with
computers or a proficient programmer,
you ll find something of interest. You'll find
15-line games and 400-line games and
everything in between.
The value offered by these books is out-
standing. Every other publisher has raised
the price of their books yet these sell for
the same price as they did in 1974.
Moneyback Guarantee
Examine one or both of these books and
key some games into your computer. If
youre not completely satisfied we'll refund
the full purchase price plus your return
postage.
Basic Computer Games costs only $7.50
and More Basic Computer Games just
$7.95 for either the Microsoft or TRS-80
edition (please specify your choice on your
order). Both books together are $15. Send
payment plus $2.00 shipping and handling
to Creative Computing Press, Morris
Plains, NJ 07950. Visa, MasterCard and
American Express orders should include
card number and expiration date. Charge
card orders may also be called in toll-free to
800-631-8112 (in NJ 201-540-0445).
Order today to turn your computer into
the best game player on the block.
Greative
Gorepatirg
Morris Plains, NJ 07950
Toll-free 800-631-8112
(In NJ 201-540-0445)
31
Tic Tac Toe or
Noughts and Crosses
Jeffrey Hoffman
On a computer with a very limited
amount of memory (1K) even a simple
game like Tic Tac Toe might be a problem
to fit. This version of the well known
game is short and simple, anyone will be
able to understand it. Lines 10 through 90
define the variables A$ to I$ (since there
are no string arrays on the ZX80 with 4К
ROM, one must use another way). Lines
120 to 160 create the familiar tic tac toe
pattern using the “checkerboard” graphics
symbol (located above the “A” key—you
must use the "shift key"). In order to save
memory, this program assumes that you
know the rules of tic tac toe, and therefore
allows you to enter any number you want,
only actually using those between one
and nine. However, you may not put an X
where there is already an O (or visa versa),
the computer will just take the number
and go on to let your opponent go. Those
people with larger memory machines can
adapt this program to include a "play
against the computer" mode. []
Jeffrey Hoffman, 332 Melbourne Rd., Great
Neck, NY 11021.
32
10 LET А$="1"
20 LET B$-"2"
30 LET C$-"3"
40 LET D$-"4"
59 LET E$-"5"
6g LET F$-"6"
70 LET G$="7"
89 LET H$-"8"
99 LET I$="9"
10)
110
120
130
140
150
160
170
18g
19g
29g
21g
45g
460
470
48g
49g
578
FOR Q-1 TO 9
PRINT " TIC TAC ТОЕ"
PRINT Аф; "5 "5;B$;" 3 "c$
PRINT " (9 3 symbols)
PRINT B "IE
PRINT
PRINT en's 1G
PRINT
IF Q-2*(Q/2) THEN GO TO 23g
PRINT "X GOES"
INPUT C
LET Рф="Х"
GO TO 27g
PRINT
PRINT "O GOES"
INPUT C
LET P$="0"
LET J$=STRİ (C)
IF J$=A$ AND NOT A$=P$ THEN A$-P$
IF J$=B$ AND NOT B$=P$ THEN B$=P$
IF J$=C$ AND NOT C$=P$ THEN C$=P$
IF J$=D$ AND NOT D$=P$ THEN D$=P$
IF J$=E$ AND NOT E$=P$ THEN E$=P$
IF J$=F$ AND NOT E$=P$ THEN F$=P$
IF J$=G$ AND NOT G$=P$ THEN G$=P$
IF J$=H$ AND NOT H$=P$ THEN H$=P$
IF J$-I$ AND NOT I$-P$ THEN I$-P$
IF А%-В% AND B$-C$ THEN 47g
ТЕ A$-D$ AND D$=G$ THEN 470
IF A$-E$ AND E$-I$ THEN 47g
IF В%-Е% AND E$-H$ THEN 470
IF C$-F$ AND F$-I$ THEN 47g
IF D$-E$ AND E$-F$ THEN 47g
IF G$-E$ AND E$-C$ THEN 47f
IF G$-H$ AND H$=I$ THEN 47g
NEXT Q
GO TO 49g
PRINT P$;"
GO TO 5g
PRINT "T I E"
REM END
WON"
SYNC Magazine
The Sinclair ZX80 is innovative and powerful.
Now there's a magazine to help you get
the most out of it.
SYNC magazine is different from other
personal computing magazines. Not just
different because it is about a unique
computer, the Sinclair ZX80 (and kit ver-
sion, the MicroAce). But different be-
cause of the creative and innovative phi-
losophy of the editors.
A Fascinating Computer
The ZX80 doesn't have memory map-
ped video. Thus the screen goes blank
when a key is pressed. To some review-
ers this is a disadvantage. To our editors
. this is a challenge. One suggested that
games could be written to take advan-
tage of the screen blanking. For exam-
ple, how about a game where characters
and graphic symbols move around the
screen while it is blanked? The object
would be to crack the secret code gov-
erning the movements. Voila! A new
game like Mastermind or Black Box
uniquely for the ZX80.
We made some interesting discoveries
soon after setting up the machine. For
instance, the CHR$ function is not limit-
ed to a value between 0 and 255, but
cycles repeatedly through the code.
CHR$ (9) and СНВ$ (265) will produce
identical values. In other words, CHR$
operates in a MOD 256 fashion. We
found that the “=” sign can be used se-
veral times on a single line, allowing the
logical evaluation of variables. In the
Sinclair, LET X=Y=Z=W is a valid ex-
pression.
Or consider the TL$ function which
strips a string of its initial character. At
first, we wondered what practical value it
had. Then someone suggested it would
be perfect for removing the dollar sign
from numerical inputs.
Breakthroughs? Hardly. But indicative
of the hints and kinds you'll find in every
issue of SYNC. We intend to take the
Sinclair to its limits and then push be-
yond, finding new tricks and tips, new
applications, new ways to do what
couldn't be done before. SYNC functions
on many levels, with tutorials for the be-
ginner and concepts that will keep the
pros coming back for more. We'll show
you how to duplicate commands avail-
able in other Basics. And, perhaps, how
to do things that can't be done on other
machines.
Many computer applications require
that data be sorted. But did you realize
there are over ten fundamentally differ-
ent sorting algorithms? Many people
settle for a simple bubble sort perhaps
because it's described in so many pro-
gramming manuals or because they've
seen it in another program. However,
sort routines such as heapsort or Shell-
_ Metzner are over 100 times as fast as a
bubble sort and may actually use less
memory. Sure, 1K of memory isn't a lot
to work with, but it can be stretched
much further by using innovative, clever
coding. You'll find this type of help in
SYNC.
Lots of Games and Applications
Applications and software are the meat
of SYNC. We recognize that along with
useful, pragmatic applications, like finan-
cial analysis and graphing, you'll want
games that are fun and challenging. In
the charter issue of SYNC you'll find se-
veral games. Acey Ducey is a card game
in which the dealer (the computer) deals
two cards face up. You then have an op-
tion to bet depending upon whether you
feel the next card dealt will have a value
between the first two.
In Hurkle, another game in the charter
issue, you have to find a happy little
Hurkle who is hiding on a 10 X 10 grid. In
response to your guesses, the Hurkle
sends our a clue telling you in which
direction to look next.
One of the most ancient forms of arith-
metical puzzle is called a “boomerang.”
The oldest recorded example is that set
down by Nicomachus in his Arithmetica
around 100 A.D. You'll find a computer
version of this puzzle in SYNC.
Hard-Hitting, Objective Evaluations
By selecting the ZX80 or MicroAce as
your personal computer you've shown
that you are an astute buyer looking for
good performance, an innovative design
and economical price. However, select-
ing software will not be easy. That's
where SYNC comes in. SYNC evaluates
software packages and other peripherals
and doesnt just publish manufacturer
descriptions. We put each package
through its paces and give you an in-
depth, objective report of its strengths
and weaknesses.
SYNC is a Creative Computing pub-
lication. Creative Computing is the num-
ber 1 magazine of software and applica-
tions with nearly 100,000 circulation.
The two most popular computer games
books in the world, Basic Computer
Games and More Basic Computer
Games (combined sales over 500,000)
are published by Creative Computing.
Creative Computing Software manufac-
tures over 150 software packages for six
different personal computers.
Creative Computing, founded in 1974
by David Ahl, is a well-established firm
committed to the future of personal com-
puting. We expect the Sinclair ZX80 to
be a highly successful computer and
correspondingly, SYNC to be a respect-
ed and successful magazine.
Order SYNC Today
To order your subscription to SYNC, in
the USA send $10 for one year (6
issues), $18 for two years (12 issues) or
$24 for three years (18 issues). Send
order and payment to the address below
or call MasterCard, Visa or American Ex-
press orders to our toll-free number.
Subscriptions in the UK are mailed by
air and cost £ 10 for one year, £ 18 for
two years or £ 25 for three years. Send
order and payment to the UK address
below.
Canadian and other foreign surface
subscriptions cost $15 per year or $27
for two years and should be sent to the
USA address.
We guarantee your satisfaction or we
will refund your entire subscription price.
Needless to say, we can't fill up all the
pages without your help. So send in your
programs, articles, hints and tips.
Hemember, illustrations and screen
photos make a piece much more inter-
esting. Send in your reviews of peripher-
als and software too—but be warned: re-
views must be in-depth and objective.
We want you to respect what you read on
the pages of SYNC so be honest and
forthright in the material you send us. Of
course we pay for contributions— just
don't expect to retire on it.
The exploration has begun. Join us.
The magazine for Sinclair ZX80 users
ш ==
39 East Hanover Avenue
Morris Plains, NJ 07950, USA
Toll free 800-631-8112
(In NJ 201-540-0445)
27 Andrew Close, Stoke Golding
Nuneaton CV13 6EL, England
Making Music with the ZX80
The Sinclair ZX80 comes with no built-
in sound device, although someday someone
will undoubtedly devise a gadget for this
purpose. Until then we can use programs
to control sounds using the weak AM signal
coming from the microprocessor. This signal
was strongest at the high end of the dial.
The basic theory behind the program is
the operating system “keeps tabs” on
the position of every FOR...NEXT loop in
the program. For example, if you write a
program similar to the one below, which
repeats two identical loops indefinitely (or
until you hit BREAK), you will hear a trill-
like sound.
10 LET X 50
го FOR I = 1 TO X
20 NEXT I
40 FUR I = 1 TO X
«aO NEXT I
40 G0 TO 20
34
Richard Forsen
The tirst loop generates the higher pitch.
It is interesting that a loop-within-a-loor
structure will not produce the same result.
The variable X represents the length of
the note. Line 10 can be changed without
affecting anything else but the duration of
the tone. The value of 50 makes the tone
last about one fifth of a second. A larger
number will increase the length of time
the note is played. Try changing line 10 to
“10 INPUT X" and line 60 to ‘60 GOTO
20,‘ RUN the program, and input thes values:
1, 2, 5, 8, 15, 25, and 64, BREAKing after
each entry. Then Add:
1 RANDOMISE
по INFUT N
10 LET X = КМП (М)
31 FOR I = 1 Ta X
32 NEXT I
зз FOR I = 1 TO X
34 NEXT I
за FOR I = 1 TO X
зе NEXT I
37 FOR I = 1 TO X
зә NEXT I
trying the same values.
ШШ JULIO ULL |
THU UNA БИ
= —
3 a ТЛ»
2
И А 22222 Kaeo |
2
| hm ти Шү | )
s ГІ ІШІП — le
SYNC Magazine
Music Making, continued... 0001 DIM L (12) (Duration for each note)
The program can be typed in quickly 0002 DIM P (12) (Pitch for each note)
due to the excellent line editor built into 0909 PRINT "HOW МАМУ NOTES?" (Up to 12)
the ZX80. Enter the first nineteen lines, 2. "add N e notes — N)
then type 1000 FORI 1 TO Xandhit 22-0 FoR I= i TON elt-explanatory)
NEWLINE. Then press SHIFT and NEW- jasc рр "НИЕАТТНМ ПЕ NOTE!
LINE simultaneously. Line 1000 will appear ша ы | DURATION OF NOTE" (1 for whole note, 2 for 1/2 note, 4 for
below the listing. Next press SHIFT 5, бел мы M quarter note, 8 for eighth note, etc...)
RUBOUT, 3 and NEWLINE. You have OOS PRINT "(1/":M:")"
now duplicated line 1000. Do this for соло LET D (1) = 576/M
everything, and you will save time. 0045 PRINT "PITCH?"; 1 is the highest pitch, 17 is the 1 |
After you've typed the program, RUN ооо ІМРЫТ РСТ) 2 PS айын ng
it. First it will ask “HOW MANY МОТЕ$?”. nos cL
Here you must enter a number from 1 to ооло NEXT I (Ends loop for inputtting data)
12. More than 12 notes will overload the o500 FOR Е = 4 TO N (Loop for playing tones)
memory, causing the program to termin- 0510 LET X = ID (Е) (Sets duration)
ate. QTO GO SUB 970 + P (F) s 30 (Plays actual note)
The computer will then ask the pitch 0320 NEXT Е (Ends loop)
and duration of each tone. When asked 0777 GO та Soo (Repeats series of tones indefinitely)
for the duration, type in the reciprocal of 1090 FOR I = 1 TO X (First of a series of 17 FOR...NEXT sub-
the actual duration. Forexample:toenter 1010 NEXT I routines that produce 17 different tones.
a quarter note, enter 4. One problem arises 1020 RETURN They go from highest in pitch to lowest.
with dotted notes. A dotted eight note 19529 FOR I = 1 ТО X No STOP statement is needed.)
counts 3/16, and the reciprocal is 16/3. 1940 NEXT I
Since you can't enter this as a numerical 19-0 RETURN |
value, you must divide it yourself. Instead 100 FUR I = 1 To X
of entering 16/3, enter 5. didis Nis d ы, T
To enter the pitch, type a number e ips TURN |
between 1 and 17. 1 represents the highest 1100 s : | = 2 A
pitch, and 17 the lowest. | | 10 RETI IRN
After you have entered the tune, the 1170 Fn R I= 1 TO X
computer will play the notes in sequence — 4156 NEXT ZEN
and then repeat the score continuously. 1140 RETURN
You can hear the composition by putting 1150 FoR I = To x be apd. тыы
an AM radio on top of the computer, or 1140 NEXT I 3 PRINT "SPEED":
vice versa. I found the best signal by putting 1170 RETURN T en ur
Changes For Sound Effector
the computer on top of my stereo. 1120 FOR I = 1 TO X AO LOT JL ER = SPECIA
The changes for two variations arelisted 1190 NEXT 1
below the main program. Thefirstprogram, 1200 RETURN If you want, you can change line 510 to
"Sound Effector,” lets you create various 1210 FOR I = 1 Та X LET X=RND(D(F)) to make it sound more
arcade type sounds. This is the same аз 1==0 NEXT I interesting.
the original program, except for being able 1:20 RETURN
to adjust the speed of the oscillations, 1240 FOR I = 1 TŪ X The second program variation, “Compu-
thereby creating interesting sound effects. 1450 NEXT I | sition," has the computer do the composing.
1260 RETURN It makes up the pitch, a number between 1
1270 FOR I = 1 TU X
1230 NEXT I
L270 RETURN
and 17, and the duration is a random
exponent of two.
1300 FOR I = 1 To X Changes For Composition
| 1310 NEAT |
< 2... 30 LET M = Z ж ж (КМО (6) -1)
M 1220 RETLIRN „=, р - pa `
Ж. 1220 FOR I = 1 TU X su PRINT 1:7.) СПИТЕ)
» 2 20 LET Р = КАМП (17)
1340 NEXT I
7, 1550: БЕТПЕН 55 PRINT P (1)
| 1 BAD FECR I = i ШЕ X НЕСЕТЕ KT д ke ы
y 1270 NEXT I
vit S80 RETURN | |
1 i290 EOR 1 = 1 тах Line 30 picks a power of 2 between 0 (1)
1400 NEXT I and 5 (32)
1410 RETURN Thesix can be replaced by any number up
1420 FOR I - 1 TO X to 10.
1430 NEXT 1
1440 RETURN
1450 FOR I = 1 TO X |
14^0 NEXT I
1470 RETURN
1420 FOR I = 1 TO X
1490 NEXT I О
1500 RETURN
35 prints duration and which subroutine
was used is printed in line 55.
|
|
Line 50 picks a pitch for P(I) from 1 to 17. |
Rich Forsen, 9496 Weston Road, New Hartford,
NY 13413.
March/April 1981 35
The Home Computer Market,
the ZXSO and the Future
I would like to describe what Sinclair
has been doing — what we are doing, and
what we plan to do. I would also like to
speculate about what Sinclair and other
companies in the small computer business
might be doing 10-15 years from now. We
are still in a very young business, none of
us has been around for more than a couple
of years, and another 10-15 years is going
to make perhaps more difference than
any of us realizes.
Sinclair is a company which has been
involved in the consumer electronics
business (calculators, digital watchs, etc.).
When we were designing calculators,
particularly programmable and scientific
calculators, we'd say, “wouldn’t it be terrific
if we could design a computer that wasn't
much bigger than a calculator, but would
be a real computer, programmable in a
high level language." It seemed as though
it would be a long time before we could do
that when we thought of it in 1973-1974.
Technological advances have made it
possible much sooner than anyone
expected.
We introduced the Sinclair ZX80 in
Europe in February 1980, and in the U.S.
in August 1980. We've sold a large number
of computers. To say that we have been
successful is an understatement. We are
still growing very rapidly. We've been selling
exclusively by mail order and primarily to
technically-oriented people. We choose
36
Nigel Searle
erpts c of -. а sp st —! given to the
ur Computer Group of New
P 1280.
our markets by the type of magazines we
advertise in and, although we are beginning
to advertise in consumer magazines, most
of our sales have come from technically-
oriented people. We certainly don't intend
that that will always be the case.
The Home Computer Market
We think that our success has proven
the home computer market, which people
talked about four and five years ago. and
which they became diverted from because
of the greater profits and the readier market
in the small business area—that true
consumer market (personal, home, etc.
but definitely not small business) — does
exist. The sales of our ZX80 have shown
that. At the same time that we are not
selling a small business computer, neither
are we selling a home entertainment
computer. The Sinclair ZX80 is not the
greatest computer on which to play "Space
Invaders." We do have such a software
package coming out, but it doesn't have
sound or color and its graphics are not
high resolution. There are other dis-
advantages from the games and entertain-
ment point of view which we will come to
in a moment.
We are selling a serious computer for
use in a particular application. Very often
that application is education— the user's
own education or his children's education.
We are selling it to individuals who are
paying with their own after-tax dollars and
not with the tax deductible money of a
business. So we have shown, I think, and
certainly we have satisfied ourselves, that
the personal computer market really does
exist and there is no reason to believe that
it won't go on growing. We are, of course,
doing some of the things which we believe
will help it to grow.
Perhaps the most amazing thing about
our success so far —and we have sold literally
tens of thousands of units, in excess of
50.000 units world wide —is that this unit
has an integer-only Basic, has just 1K bytes
of RAM, has virtually no application
software, and has no off-the-shelf peripherals
as of today. Obviously we expect the market
to grow as we provide those things. The
highest priorities on our own list, i.e., items
that will be manufactured by Sinclair, are
a 16K RAM module, which comes in a
small case about 2.5" square and plugs in
to the back of the main board through an
edge connector.
Our next add-on option for the unit will
be an 8K extended Basic, which will no
longer be integer, but will be a fully floating-
point Basic with multi-dimensional arrays,
powerful string handling capabilities and
a whole host of other features. I dont
think it is an exaggeration to say that just
as our 4K integer Basic is considerably
more powerful than Radio Shack's Level I
SYNC Magazine
Basic, so our 8K Basic will be considerably
more powerful than Radio Shack's Level
II Basic and, indeed, more powerful than
Microsoft's 8K Basic. We are also working
hard to produce exciting applications
software.
Consider VisiCalc. It stands almost all
alone as a software package, it is so good
that people buy computers just to use
VisiCalc and never use their computer for
anything else. It may be that VisiCalc is
the only software package that justifies
the $1000-$2000 expenditure to buy an
Apple, Atari, Commodore or whatever.
We envisage that there will be a lot of
software packages that are to the ZX80
what VisiCalc has been to those larger
computers. Our software packages will
certainly be very powerful, but it doesn't
take as much to persuade someone that it
is worth going out and spending a couple
of hundred dollars to be able to use a
particular package. We have some software
packages, which are scheduled to be
released soon that I think are going to be
as well known a year from now as VisiCalc
is.
Not only has Sinclair satisfied itself that
there exists a huge consumer market, but
other people also have been persuaded
that there is a large market. Consequently,
Sinclair is not the only company that is
working to support the basic product. In
addition support provided by publications
such as SYNC magazine, there are at least
three independent companies that are far
advanced in their plans to manufacture
and market hardware and peripherals for
the ZX80, including a general purpose
interface which will include ап RS-232
and also support disk drives. There are
numerous companies developing software
and printed materials. Image Computer
Products is the semi-official software
supplier in the U.S. for the ZX80. While
most of the programs in their current
catalog, because they are designed to run
on the basic 1K machine, are certainly no
great advance on anything you have seen
before, Image is working hard on more
advanced, complex programs which will
be available as soon as the larger memory
and extended Basic are available.
March/April 1981
ZX80 Features
Some of the features of our machine
that make it appealing to the first time
user include the following:
Any line of Basic or command at the
system level that you enter to the machine
will appear at the bottom of the screen.
When you enter a line into the program it
will go to the top of the screen. The cursor
originally appears as a "K." for "keyword."
a Basic command word. As long as you
only enter digits they will be entered and
the cursor will move along and remain in
the “К” mode. As long as the cursor is in
the "K" mode you can enter at asingle key
stroke any of the Basic command words
that are available. It will be entered and
appear in its full format as a result of a
single key stroke. So without the use of a
shift key or anything else you can hit a
single key and get "SPACE PRINT
This feature eliminates a great deal of
typing and is extremely convenient when
you get used to it. More importantly, the
ease of input is mirrored by the simplicity
and economy of storage, because the seven
characters involved in "SPACE PRINT
SPACE" are stored internally as a single
byte. Offering a machine with only 1K
bytes of user memory, we had to,be very
mean in our use of memory and thus we
have employed a number of tricks, or data
compression techniques, to minimize the
amount of memory the program storage
takes.
The 1К bytes of user memory are
dynamically allocated between program
storage, working space and display. There
is no separate video circuitry in the machine.
As you get close to your memory limit
with a program being stored, you have a
decreasing amount of memory available
for the storage of the information which is
to be displayed to the screen. You then
have tolook at the results of your program
in chunks. It will display as much as it
can —usually a full screen, but sometimes
3/4 full—and then you have to continue
execution to see the remaining results.
Obviously with a 16K memory it is going
to be relatively rare that you would run
into that constraint. The boundaries in
the memory are not fixed; there is no
memory mapping.
If you enter a character such as + (plus)
and say PRINT +, the machine recognizes
that that is syntactically incorrect. That is
not a meaningful statement in the Basic
language. There is no way that a PRINT
-Fcan ever be continued in such a way as
make it a statement, therefore the
machine, indicates with the symbol ''S" a
syntax error. By its position it tells you
where the error is located and, thus you
must make a change at the point
indicated before the line will be accepted
into a program.
If you are a beginner learning to program,
you won't have the frustration of entering
a large program only to find at run time
that you have put a comma at every place
you wanted a semi-colon or that you misused
some other feature of the language. You
will be made aware of any syntax error in
your program before you can complete
that line of the program.
One of the disadvantages of the machine
which makes it unsuited for games appli-
cations is that the microprocessor drives
the display. Consequently, when it is
computing it isn't displaying and when it is
displaying it isn't computing. When you
tell it to EXECUTE a program, it goes
ahead and EXECUTES the program and
when it is finished it displays the results. It
tells you at the bottom where the execution
terminated and what the termination
condition was. Because we never allow a
program to be entered with syntax errors
in it, the termination errors are few.
After manufacturing was started, some
of our workers decided to make the ZX80
compute and display at the same time.
They were successful, and there will in
some future version of the ZX80 be the
facility to compute and display. Some people
have already written machine code routines
which enable the existing machine to display
and compute. It is programmable in Z80
machine code but there is not an assembler
available at the present time. There are
PEEK and POKE commands and you must
enter the machine code instructions one
ata time with a POKE command. You сап
then call and execute them with a USR
command.
Future Speculations
I would like to take the opportunity
now to speculate. I am going to present
some fantasy rather than fact, but I believe
37
Computer Market, continued...
that it is in the nature of most science
fiction — fiction that will come true.
I think we are going to see the develop-
ment of at least three different types of
what have hitherto been known as personal
computers, to serve the needs of three
distinct markets. One of those markets
will be the small business market; one will
be the educational market; and the third
(of which the ZX80 is perhaps the first)
will be a market for truly personal consumer-
oriented computers.
Within each of these markets, let's
consider three elements of computer system
design. In particular, what will be the
primary means of input to a personal
computer? What will be the primary method
of data and program storage? What will be
the primary means of output?
Future Types of Input
Each of the three markets— business,
education and personal—have different
needs in each of those areas. If one allows
one's imagination to run wild it would seem
that the most convenient method of input
for a personal computer would be to
communicate with it the way we com-
municate with anything else that we think
is intelligent, the way we communicate
with other human beings. That is, we should
be able to speak to it and have it understand
us in a fairly free format manner.
Obviously, a lot of people have thought
about that and some people have done
something about it. In fact, one company
sells a voice input peripheral for less than
$120 and is going make a version of it for
the ZX80. At this stage, it’s capability is
limited to a small number of commands
that you have to speak fairly consistently
in order that it will understand. I have no
doubt that speech input will be the primary
method, if not in the next 10 years then in
the decade following, for the personal/
consumer computer.
When you come to the business com-
puter, I think the keyboard is going to
remain the dominant method of entry.
Business has a huge pool of people who
are used to using keyboards, who can use
them very effectively, and will continue to
do so. The typical business executive is
38
not going to be interested in learning to
use a keyboard any more than he or she
has been interested in learning how to use
a typewriter, a copying machine, or any
other piece of equipment in his or her
office. The business executive is not even
going to be interested in learning how to
talk toit. It will always be easier for him to
buzz his or her secretary on the intercom
and say "Do this or that on your computer
or computer terminal." It is going to be
easier for him or her to get something
done than to do it for himself. Consequently,
I think the primary method of input for
small computers in business is going to be
via a typewriter keyboard by exactly the
same people who use keyboards now in
business.
On the other hand, the educational
market has, at a certain level, a requirement
for input that isn't served by either voice
or keyboard input. I’m thinking of the
young child for whom I think the personal
computer is going to be a large part of his
or her life and education. Clearly that
child is not going to be able to use a keyboard
with facility, nor is the child readily going
to be able to learn to speak to the computer
ina way that the computer will understand.
In fact, one reason that child will use the
computer for education is that he or she
cannot do those things with facility. I think
the primary method of input for the home
education market is going to be a touch
sensitive screen.
So we have for the three main market
areas three methods of input: speech for
the consumer computer, keyboard for the
business computer and touch video for
the educational market. I don't want to
suggest that these are the only methods of
input that are going to exist or that they
are the only ones that are going to exist in
those markets, but I think they are the
primary ones.
Memory and Data Storage
Just as we have found out that the disk is
more convenient than cassettes, I think
we will find that bubble memory or some-
thing of equivalent capacity, convenience,
speed and low potential cost will be far
superior to any medium such as disk, stringy
floppy or cassette where you have one
device that reads and writes the data and
another medium on which you store the
data. For both the consumer and business
markets, I feel the primary method of data
storage is going to be bubble memory or
its equivalent if it is overtaken by some
other technology with similar but improved
characteristics. |
In the educational market there may be
a need for something that will look very
much like a video disk. There seems to be
a demand for a large quantity of data in
excess of what can be stored within any
affordable amount of bubble memory. The
same programs which teach a child a given
discipline in 1990 will probably be perfectly
adequate in 1995. So there is a demand for
a huge amount of data that does not change.
I think that the video disk or something
very similar to it is going to meet that
need.
In the business and consumer markets
there will be a heavy dependence upon
remote data banks, with software programs
and data being down loaded from a larger
system at high speed over a telephone
line. I foresee problems with being in
constant communication with a remote
data bank, but I feel the down-load mode
is going to be extremely important. It also
solves what otherwise will become a major
problem of piracy of both software and
data. It will be cheaper for a one-time
download than to make a copy and have a
means of storing that data or software.
Output in the Future
For the consumer computer I have no
doubt that the primary form of output is
going to be video. It has the huge advantage
that most of us can and still will be able in
20-30 years time to read. We can take ina
lot of data at once, far more than we can
hear. We can see far more at a glance on a
screen. The screen need not be large as
long as the resolution is there, a screen of
2"diagonalis more than sufficient to present
the information that most of us would
require. We can look at a 2" screen with
sufficient resolution and see what we want
as readily as we can look at a 2”photograph
or read that area on the page of a telephone
book.
In the educational area video is not so
useful. Although I have suggested a touch
sensitive screen, probably more important
to the educational market for the child is
sound output. A child will respond to sound
SYNC Magazine
better than to video. It will capture his
attention when his attention might have
wandered from the screen. It will convey
information to the child which cannot be
given visually because the child can under-
stand the spoken word but can't read with
great facility. Indeed the computer might
be doing the job of teaching the child to
read.
In the business market, I forsee primarily
printed output. Again, there will be a screen
on the small business computer or office
terminal. But for the same reasons I cited
before, when a business executive wants
to see last week's or yesterday's or the last
hour's sales figures, he or she will push a
button and say, "Get me the sales figures."
The screen and the keyboard will be outside
the executive's office. Somebody will key
in the information necessary to get the
required data, and that data will come out
on a sheet of paper, which can be handed
to the boss. That is the way business
executives deal with information —on paper.
I think there will be a major problem getting
them to deal with it on a screen.
That is not vastly different from the way in
which computers are being used today in
schools, although the system I am speaking
about will be widely used in homes. How-
ever, while I say the system will not look
that much different from the ones in use
today, it will be vastly more powerful and
less expensive.
Itisin the personal area, in which I have
suggested that the ZX80 may be the first
computer, that I see the greatest change. І
have suggested that the computer will have
speech input and video output, for which
а 2-3” diagonal screen will be quite sufficient.
The memory will be of a bubble type that
will be extremely compact and in which
we will see the same type of advances that
we have seen in semi-conductor memory
over the last 15-20 years. The only other
thing that will be needed is some means of
connecting this computer to a telephone
line so that you will be able to get data
down-loaded from a large computer. Just
as calculators took 10 years to get to their
present size, so personal computers will
be the size of the calculators of 10 years
ago. And they will incredibly inexpensive.
In the business market I see something
that is going to be operated by the people
who today operate typewriters. It will look
exactly like a typewriter with the addition
of a screen. It is going to look like one of
today's word processors. It will have a
keyboard to key in information and a very
extensive solid state memory of its own. It
will be connected remotely to larger
computers and will have printed paper
output. It will also have a screen for editing,
word processing etc., but that will not be
the primary method of output. Strangely
enough, I don't see, in the one area that
has already adopted small computers, a
great deal of change.
In Summary
In education, I see a computer with a
screen that will serve as an input device
almost as much as an output device with a
heavy dependence on sound output. It
will probably have some voice input,
depending on the age of the child and, in
many instances something equivalent to a
video disk that has the lessons—in David
АҺ words, the “courseware” —on the disk.
March/April 1981
Ubiquitous and Essential
However, what will be expensive is the
capability to utilize the power that will be
put in your hands, and I think that will
create a major social change. Not because
there will one group of people who can
afford the "credit card computer" and
another group that can't: the question is
who will choose to use it? Who will have
the imagination and the basic education
to use it? Maybe with the use of computers
in education everybody will, but initially I
think there will be a two groups of people
that have been described by someone else
in contrast to the haves and the have nots.
These will be the “knows” and the "know
nots." There will be some people who will
know how to gain access to and manipulate
for their own advantage just about any
piece of information they can possibly wish
to have. The "credit card computer" will
revolutionize the way you do your job and
the way you live your life. This card will
replace all the others. It will be your
electronic funds transfer card; it will be
your personal ID; it will be everything. It
will be so important to you that if you use
it and integrate it into your life, you would
no more go out of your house or indeed be
anywhere in your house without your card,
than you would without your clothes. About
the only place you won't have it with you
is in the shower.
I hesitate, but only momentarily, to go
one step further and suggest that instead
of looking 15 years ahead we double the
period and look 30 years ahead. You may
have the opportunity in 30-40 years time
literally to insure that you will no go
anywhere without your computer because
it will be inside your body. Of course that
will require that it be interfaced with your
brain so that all you have to do is think
that you would like to know the contents
of page 73, volume 21, of The Encyclopedia
Britannica, and no sooner will you have
thought it than you will see it. That I
believe is not impossible. I am not sure
that it isn’t dangerous. I know what is
dangerous, and that is to think that it is not
possible, if indeed it is going to happen.
That is really dangerous. So whether we
like it or not, whether we are scared by it
or not, it is something that we need to
think about. O
Blank Cassettes
The quality of cassette tape used to
save and load programs is an important
factor in getting the programs to run.
Tape quality for computers is measured
differently from quality for audio tape.
The tape must be capable of sending to
the computer the electronic signals of
the program without transmitting extra-
neous noises that could interfere with the
ability of the computer to load the tape.
Our blank cassettes are tested and
recommended for computer use. C-10
cassette, 5 min. per side, blank label on
each side in a Norelco hard plastic box.
[0010] $1.25 each.
Head Cleaner
After hours of use, the read/write head in
a cassette recorder will pick up minute
particles of tape oxide. This dirt will hardly
be noticable in dictation or music. But it is
very noticable in computer use. One dropped
bit in 16,000, and the program won't load.
Help keep your recorder in top shape
with our non-abrasive head cleaner. It consists
of 18 inches of stiff cleansing fabric in a
standard cassette sheii. One 10-second pass
every 40 hours of use will keep your heads
as good as new. [0011] $2.00. Send pay-
ment plus $1.00 Shipping per order to:
Peripherals Plus
39 East Hanover Avenue
Morris Plains, NJ 07950
39
puzzles S problems
“1, Merlin, challenge the readers of SYNC to a battle of wits. Every issue I shall propound a series of
problems for you to solve. They will vary in complexity and category and should prove an interesting
diversion between articles. I also welcome contributions from our readers. If you have a favorite puzzle you
feel will be of interest to us send it in. If I use it I shall send you a copy of one of my famous MERLIN'S
PUZZLER books.
“And now to work! Our first puzzle is called...
THE — JACK PUZZLE
his is a great old puzzle. Draw upa
М rough board like the one shown at
УЙ ( the right. Place a checker in every
|| square that has a letter in it. Your
ШІ problem is, starting with the
| checker in the square marked “1”, to
remove all of the checkers from the
board, save one, and have this last
checker end up where you started in
square one. You can jump one
checker over another checker in any direction, side-
ways, up and down, or diagonally. Whenever you
jump over a checker you must remove it from the
board. However, as in checkers, the square beyond
the checker you are jumping over must be empty. A
continuous series of jumps, using one checker, will be
considered to be one move. You must solve the puzzle
in just four moves. On your mark, get set, start
jumping!
ээ
THE BARREL PUZZLE
OW, this puzzle should prove to be “barrels of fun” for all of you! Printed on the three
barrels pictured below are the numbers “1,” *6" and “3.” Can you rearrange these barrels so
that you have a 3 digit number that can be evenly divided by seven? The answer is quite
ingenious.
| 1) (9) (5)
THE GOLDEN HELMET PROBLEM
he management at the Peabody Helmet Company
/ discovered that one of the ten artisans that make their
/ line of solid gold helmets has been cheating them. It has
been determined that one of the men has been using
one ounce less gold per helmet than required, and, he
has been keeping this ounce of gold for his own use.
Mr. Peabody, a man who is always in a hurry, has
decided that he can determine who the thief is with just one weighing
on the large company scales. One thing should be pointed out, each
artisan stamps his initials inside each helmet that he crafts. Now, how
THE DOUBLE HORNED ZAT PUZZLE
could he find out, with just one weighing, who the guilty party is?
Y ur last puzzle comes from the book "Merlin's Puzzler 2" and is called The
(e) Double Horned Zat Puzzle. (See the drawing at the left). Merlin claimed that
C ре is a very powerful magical sign and is useful in warding off pests, the
humors, and bill collectors. To generate the maximum amount of magical power you
must draw the sign using one continuous line. Also, no part of the line may cross over
any other part of the line.
Now, practice well, you never know when a good hex sign will be needed.
Answers on page 44.
I hope that you enjoyed Merlin’s puzzles. Now. don't forget, if Your editor,
you would like to try and stump our readers with one of your own p ptt
puzzles, just send it along. If Merlin uses it he will send you a copy of ZZ А Ж bu
one of his books that deal with puzzles, games and magic.
So long until next time... Charles Barry Townsend
40 SYNC Magazine
Problems for
Computer Solution
Here are 90 problems with a thorough
discussion and references for each.
Eleven types of problems are included,
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The teacher's edition contains solu-
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Katie and the
Computer
Fred D'Ignazio and Stan Gilliam. This
is a delightful story told in words and full
color drawings of Katie's adventures
when she "falls" into a computer. In
Katie's journey through the land of
Cybernia she meets the Software Colo-
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even a ferocious Program Bug. Her
journey parallels the path of a simple
command through he stages of pro-
cessing in a computer, thus explaining
the fundamentals of computer operation
to 4-10 year olds. Supplemental explan-
atory information is contained in the
front and back end papers. 42 pp.
hardbound $6.95. (12A)
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Reviews
Jonathan A. Stein
7Х80 Programs
ZX8&0 Programs, Volume 1 edited by
Chris Denning; published by Zipprint, 418
Poole Road, Parkstone, Poole, Dorset BH12
1DF, England. 82 pages, paperback. £5.25
in the U.K.; $13.00 in the United States.
Although intended for all ZX80 users,
this book is aimed especially at people wih
little prior computer experience. The book
contains twenty programs, of which nine
are "practical" programs for business and
home, three are for educational purposes,
and eight are games.
Stock List, one of the utility programs,
is intended for keeping an inventory of
your stocks. Although the program will
only hold thirty entries, this problem can
be bypassed by storing several copies on
cassettes.
The next utility program, Wavelength/
Frequency Conversion, converts wave-
length measurements from kiloherz to
meters, and vice versa. This function may
be useful for people in The United Kingdom
to convert radio station dial locations from
meters to kiloherz, in which imported radios
are calibrated.
The VAT Calculator program was
intended to calculate the 15% sales tax
found in The United Kingdom, although
any tax rate may be entered. This program
determines the amount of tax paid, when
only the final total is known; it does not
calculate the tax to be paid on the original
purchase price.
The educational programs are Basic
Maths (Add/Subtract) and Basic Maths
(Mulitiply/Divide). Both present drill and
practice excercises, offering three levels
of difficulty, as well as *emergency" features
which provide the answer if the student
cannot solve the problem. The two math
programs share many of the same lines,
making it possible to avoid much of the
tedious process if the first program has
already been saved.
Prime Number Tester,is an educational
tool to allow to the user to determine
whether or not a number is prime.
The game, Brain Teaser, is a pattern
matching game, similar to the hand held
electronic games, Simon or Einstein, in
which the player must duplicate a pattern.
In Brain Teaser the pattern is a series of
twenty numbers, presented individually,
with two levels of difficulty. When the
game is concluded, either by an incorrect
entry, or by successfully duplicating the
series, the program posts the score out of
the possible twenty correct turns.
The next program, One Arm Bandit
simulates the operation of a slot machine.
For each turn the player is charged 5p,
and may win from 10p to 70p depending
on his luck. By changing lines 90 through
120, the program may be altered to suit
other forms of currency.
Some of the utility and educational
programs in ZX 80 Programs, Volume 1
are worth while and several of the game
programs are quite good. Unfortunately,
the typewritten copy and hand scrawled
programs make it difficult to read. Г]
ZX80
Pocket Book
The ZX80 Pocket Book) by Trevor
Toms; Phipps Associates, 3 Downs
Avenue, Epsom, Surrey. KT18 5HQ,
England. 109 pages, spiral bound. 4.95.
The ZX80 Pocket Book differs from
other books about the ZX80 because it is
aimed at the experienced programmer.
The book begins with a review of the
Sinclair Basic, which unlike the sections
in other ZX80 books, merely highlights
this material from the original manual,
instead of repeating it at length.
The section on programming is parti-
cularly valuable because it offers simple
tips on how to become a better program-
mer, as well as suggestions on how to
better use many Z X80 features. This sec-
tion is not a how-to programming
manual, but is a well presented chapter
on improving programming technique.
The chapter, "Program Storage and
Retrieval," offers useful instructions on
how to safely save programs on cassette.
The tips presented are both those of the
author and Sinclair.
Section 5, "Data File Storage and
Retrieval,” discusses how to preserve
both data and programs without using
the DATA statment present in other
Basics. The authors suggest saving impor-
tant files in triplicate to ensure that the
information will not be accidentally
erased.
The ZX80 Pocket Book also contains
thirteen programs, including a Machine
Code Conversion and a Share Valuation
program which keeps track of shares of
stock and the price at which they were
purchased. This latter program requires
3K of RAM.
The final full section of the book pre-
sents all the ZX80 Basic commands and
explains how they are used. Examples are
offered, so one may easily see what these
commands are intended to do.
The ZX80 Pocket Book ends with five
appendices for the instruction set, the
ZX80 Character set, graphics, error
codes, and a command summary.
Phipps Associates has succeeded in
giving the ZX80 community a useful,
attractive volume at a moderate price. (0
SYNC Magazine
The ZX80 Magic Book—A Review
Jonathan A. Stein
The ZX-80 Magic Book is published by
Timedata Limited, 57 Swallowdale,
Basildon, Essex, England. 60 pages, soft-
bound, £4.75. |
This book offers both programs and
instructions on how to make better use of
this popular computer. The second half
of the book contains material which
helps one to understand how the ZX-80
works.
The text explains how to create and
debug programs, how to convert from
other Basics, and includes such informa-
tion as instructions for improving the
television picture, how to connect a
video monitor in place of a television set,
and other useful technical information.
The twenty-one programs include
Russian Roulette, which I hope no one
takes too seriously; Moon Lander, a ver-
sion of Lunar Lander, which is quite a
difficult game; and a 2K version of
Hammurabi, which is one of the best ZX-
80 games I have played. This well known
computer game was the subject of the
SYNC Challenge last issue. As the ruler
of ancient Sumeria, you must make all
vital decisions on how to run the city,
such as: how much grain is allocated for
food and seed, how much land is traded
for grain, and vice versa. On each turn
you are told how much land and grain the
city has and how the population fared
from your previous decisions. If you
calculate carefully, the population
increases, and the area of the city grows.
If not, people starve and the city loses
land.
The other games are a mixed lot —
some good, some not as good. A few non-
game programs are also included such as
Sums Tester and More Sums. The ZX-
80 Magic Book should be a useful addi-
tion to most ZX-80 libraries, particularly
for its technical sections. О
í T
ZN
March/April 1981
А Review
and Breakout
The shared use of the microprocessor
chip in the ZX-80 for computation and
screen display makes continuous graphics
difficult. The screen flashes whenever you
input information, an effect that may be
considered undesirable in a game.
The Amazing Active Display is a hybrid
program containing machine language in
a Basic program. The machine language
routine allows a continuous display on the
screen. In the program, a machine language
program, stored as hexadecimal code, is
converted into decimal numbers and
POKEd into the computer's memory. The
machine code includes calls to several ROM
routines, but bypasses the blanking of the
screen.
This program is intended for use in your
own application programs, for uses such
as animated graphics, games requiring
updates to the screen, instrumentation,
and debugging. You can provide a program-
mable pause in a Basic program with a
screen display.
The Amazing Active Display
Joseph Sutton
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Breakout is a ga rogram using the
Amazing Active Display, and shows what
can be done with the program. It also
comes as a Basic program with the display
routine listed as Hex characters.
With real time action and challenge,
Breakout is one of the best games yet
available for the ZX-80. There is a continu-
ous display at the top of the screen of a
wall of blocks, and a graphics block
bouncing up and down with a smooth
continuous motion. The player must move
a paddle at the bottom of the screen using
the arrow keys (5 and 8). Each time the
moving ball hits a block at the top of the
screen, that block is removed. If you miss
the ball with the paddle, you lose it. Once
you manage to clear all the blocks off the
screen, the ball bounces aimlessly around.
There is no victory routine.
stop the game is to unplug the
computer. The Break key does not function.
The instructions are quite minimal, and it
may be difficult to understand the program
well enough to use it in your own pro-
grams.
We like both programs, and enjoyed
playing with them.
The Amazing Active Display ($20/£10)
Breakout ($20/£10)
K. MacDonald
26 Spiers Close
Knowle, Solihull West Midlands, B93 9ES
Great Britain
Joseph Sutton, 170 S. Hillside Ave., Succasunna,
NJ 07876.
puzzles № problems answers)
The Jumping Jack Puzzle: Jump / over M, N, F,
D, C, A, B, G, O, Q, Pand K. Next play L over
H. Then play J over E and L. Your last play is
I over J. (If you have any trouble following the
answer place “letters” оп top of the checkers to
make it easier to follow).
44
The Golden Helmet Problem: Mr. Peabody
would take | helmet from worker A, 2 helmets
from worker В, 3 helmets from worker C, and
so on. He would then put all 55 helmets onto the
scales. If the total weight of the helmets was 1
ounce less than the weight of 55 helmets should
be than worker А would be the guilty party. If
the weight was out by 2 ounces then the thief
would be worker B, etc.
The Barrel Puzzle: Turn the six upside down.
You now have a 9. The number we want is 931.
The Double Horned Zat Puzzle:
SYNC Magazine
The ZX80 Companion —A Review
Jonathan A. Stein
The 27Х80 Companion, by Bob
Maunder, Terry Trotter, and Ian Logan;
Linsac, 68 Barker Road, Middlebrough
TSS 5ES, England, 128 pages, softbound,
£10. Available in The United States
through Image Computer Products, 615
Academy Drive, Northbrook, Illinois
60062, $19.95.
This book is designed to supplement
the original ZX-80 manual. It includes
tips on the operation, assembly, and pro-
gramming of the ZX80 for maximum
effectiveness. Although the original
manual is useful, and gives a beginner
clear, concise directions on the operation
and programming of the computer, The
ZXó0 Companion continues beyond the
offerings of that manual.
The book is divided into six chapters,
and has two appendices. Chapter One,
“Operating the Z X80," has five sections,
explaining basic operating procedure for
The ZX80. This section contains many of
the tips contained within the authorized
manual, although there are hints not
found in the Sinclair booklet.
March/April 1981
The second chapter, entitled “Theory
of Computers," is especially useful for
computer novices, since it explains what
computers do and how they function.
This portion of the book also examines
computer languages, and the compo-
nents of a computer system.
Chapter three, ^ZX80 Basic,” explains
the particular language of this computer,
and focuses on the individual functions
and how they are used. This section
includes the sub-headings: Assignments
and Calculations, Input and Output, Con-
ditional and Unconditional Jumps and
Loops, Arrays, Character Handling, and
Machine Code.
The fourth chapter, "The 7Х80
Monitor," looks at the monitor, and
explains PEEKing. POKEing. and sub-
routines. It also contains sub-routine
memory maps and monitor maps, as well
as a cursor table and a discussion of
ZX80 machine language. This portion of
the book will be particularly helpful for
the serious programmer.
Chapter five offers assistance in con-
structing the ZX80 kit, which is available
in the UK, although some of the advice
may apply to the construction of the
MicroAce. The authors have presented
some suggestions which augment the
factory manual.
The final chapter of The 7Х80
Companion contains programs from the
Linsac tape collection. These programs
are generally good, with The Maze game
being one of my favorites. The Spelling
Quiz program will be quite useful as a
study aid for small children.
The final pages of the book contain
two appendices, which include a compar-
ison of Z80 instruction codes and the
Z X80 character set, and a preview of the
original Sinclair 8K ROM.
The ZX80 Companion will make a use-
ful addition to most 7Х80 libraries.
There is much helpful and informative
material in the volume, although some
material covered in the owner's manual is
repeated. As useful as it is, the price
seems high when one considers the
undistinguished printing and binding. 0
45
Disassembled Basic, Linsac, 68 Barker
Road, Middlebrough TS5 5ES, England.
48 pages, paperback.
Linsac has published a disassembled
listing of the Sinclair Basic. What, you
may ask, is a disassembly? Well, wben
machine language is placed in memory,
either in RAM or ROM, it is stored as
numbers. These numbers represent
machine-language instructions, called
“mneumonics’ since they are abbreviated
versions of the command. For example,
an increment instruction is represent as
INC. When a programmer enters a program
using these or op codes, an assembler is
used to turn the commands into numbers.
A disassembler reverses the process, turning
the numbers into lines of code so humans
can understand it.
A few lines of disassembled code look
like this:
loaded. Loading a register with a value
from a memory location requires three
bytes, one for the load command and two
for the value of the location. The third
column is for labels. In this case, the labels
used are just the locations of the commands
prefaced by an L (labels must start with a
letter, though they can contain numbers).
There are two uses of labels. First, when
assembling the code, you can refer to the
label instead of the location. Thus, if you
have a segment of code that multiplies
two numbers, you could label it MULT.
When you wanted to jump to that code,
you could say JP (for jump) MULT. When
the program is assembled, the correct value
for MULT will be inserted.
The other use for labels is to make the
code easier to read. When you are scanning
a disassembly and see MULT, you know
you have found the multiplication routine.
O7BE 2E LO/BE DEL HL. ЖЖІМТЕЕКРБЕТЕКЖЖ
О?ЕҒ 222640 LD (1.4026) „НЫ. SDAVE FROG ADDRESS
Q7C2 210000 „р Н, LOOO s ZERO НІ
O7CS OQ NOF + AND “МЕЦ” CODE
O7C& 221240 L.D (1.40190 a HL ; ZERO POINTER
O7C9 211940 LU HL.,L.4019 ;FOINT TO SYNTAX FLAGS
O7CC CR6E БІТ a CHL) TEST IMMEDIATE FLAG
OZLE 2807 JR Lg lLti7 D7 r JUME IF IMMEDIATE
The first column contains the memory
locations of the code. In this example, the
code starts at hex address 7BE. The next
column shows the hex value or values for
the command. Commands require from
one to three bytes, depending on how much
information is required. For instance,
decrementing a register requires only one
byte. Loading a single register with a number
would require two bytes, one for the
command and one for the number to be
46
Unfortunately, the Linsac disassembly
doesn’t use this kind of label, making the
listing harder to decipher. The label LO7BE
tells us that the line is at 7BE, but doesn’t
give us any useful information.
The fourth column contains the mneu-
monics, followed by any values used by
the commands. The final column contains
comments, making up in part for the lack
of meaningful labels. The comments help,
but they are vague in places.
David Lubar
Stepping through the code, the first
command decrements a pair of 7-80 regis-
ters called H and L. Next, the value in
these registers is stored in memory. The
HL registers are loaded again, this time
with values from another area of memory.
The NOP command stands for “no opera-
tion.” Possibly, this byte was left open for
future changes in the code, or was created
by an earlier change in the code. The
comment isn’t clear. The next two com-
mands again place the register values in
memory and reload the registers. The BIT
command tests a value stored in location 5
to see whether the command is from a
program or from the immediate mode. If
the command is immediate, the zero flag
is set. The next line jumps to 7D7 if the
zero condition is met. Otherwise, the
program falls through to the next line (not
listed here).
With a disassembled copy of Sinclair
Basic in hand, an experienced programmer
can work wonders. He can access any of
the Basic functions through calls to the
monitor, using the USR function. Even
more powerful is the potential to use the
Basic subroutines from machine language
programs. There is no need to write your
own PRINT subroutine when you can go
through one that already exists in the
monitor. In essence, the disassembly puts
the full power of Basic at the programmer's
disposal, even when he is writing programs
in machine language.
The listing comes fully commented, with
asterisks marking the function of each
subroutine, such as *LIST*, and *PRINT
CHARACTER*. As mentioned earlier,
there are places where the comments could
be clearer. The printout is a Xeroxed copy
of a dot-matrix listing, but itis legible. The
listing, including a table of referenced lines,
is 48 pages long.
Besides being a good tool for program-
mers, this book could also be used by
someone who is learning Z-80 code. By
seeing how the commands are used, and
what the results are, you can gain an
understanding of this machine language.
SYNC Magazine
This section is intended to preview the
peripherals and accessories that will be
available for the ZX80. Readers are encour-
Product Preview =
aged to submit reviews of products men- =
tioned here.
CAI Instruments of Midland, Michigan
is developing a series of interfaces for the
Sinclair ZX80. The company has announced
a PC board which will plug into the ZX80
expansion port, in front of the 16K RAM
module. This peripheral will work with a
printer and includes an improved interface
for storing programs on tape. The basic
package includes the board, printer and
tape recorder, and will sell for approximately
$200. Other packages will be available with
varying qualities of printers and recorders.
One system, containing a printer, the board,
and a high quality tape system will cost
less than $350. CAI is also working on a
full size plug-in keyboard for under $50.
The company also has interfaces to work
with floppy disks. CAI Instruments, 2559
Arbutus Court, Midland, MI 48640.
NOW APPEARING
Innovision of Los Altos, California is
devising an improved graphics device for
the ZX80. The company will have a hand
printed graphics system using memory
mapped video. This peripheral will be
available once the 8K ROM is released.
Innovision, P.O. Box 1317, Los Altos, CA
94022
Voicetek of Goleta, California has been
authorized by Sinclair Reasearch Limited
to develop a speech recognition unit. The
project has been delayed until the intro-
duction of the ZX80 16K RAM. Voicetek,
6690 Abrego, Goleta, CA 93017.
Sinclair Research Limited now expects
to have the 8K Basic ROM for the ZX80
available by March 1981. The new Basic
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allows the use of floating point arithmetic
to nine digit accuracy, and contains log
and trig functions with inverses. This ROM
facilitates improved graphics, and contains
37 new functions including DRAW, DATA,
ARCSIN, VAL, and SCROLL. The plug-
in conversion includes a new keyboard
template and a supplementary manual, and
should sell for $40. Sinclair Research Ltd.,
50 Staniford St., Boston, MA 02114.
Sinclair has also officially announced
the long-awaited 16K RAM expansion for
the ZX80 computer. The module has
received FCC certification and is expected
before the end of January 1981. The unit is
housed in a plastic box the size of two
cassette tapes, and plugs into the expansion
port at the rear of the computer. Sinclair
is now taking orders for the $99.99 RAM.[]
Resources for the ZX80 and MicroAce
In the last issue SYNC presented a list
of 24 companies and organizations with
products related to the ZX80. Below there
is a supplement to the original resource
list. If you missed that first issue. send
$2.50 or £1.25 to SYNC, and we will gladly
send it.
We welcome entries from manufacturers
and readers for the resources column. Please
include the name of the item, a brief
description, price. and complete data on
how to obtain it. Send contributions to
SYNC Resources, 39 East Hanover Avenue.
Morris Plains. New Jersey 07950.
Software
Six programs for the ZX80 — £4.95 U.K.
Bramwell Enterprises
87 Anderson Crescent
Great Barr. Birmingham B43 7ST
England
Graphics for the 1K ZX80
C12 Cassette with four programs : Symmet-
rical Patterns. Large Print. Draw a Picture.
Plot a Picture
Cassette and manual — £ 8.00
Graphics manual only — £ 3.00
Bridge Software
36 Fernwood
Marple Bridge
Stockport. Ches. SK6 5BE
England
Self-Instruction Courses for the ZX80
Cambridge Learning Ltd.
Unit SS
Rivermill Site
Егее Post. St. Ives
Huntingdon.
Cambs. PE17 BR
England
Assorted games packages for the ZX80
4K — £5.95 and — £9.95
Database Consultancy
105 Fairholme Ave.
Gidea Park. Romford
Essex RM2 5UR
England
Assorted software for the ZX80 Kala —
£2.75
Hewson Consultants
7 Grahme Close
Blewbury. Oxfordshire QX11 9QE
England
48
The ZX80 Pocket Book — £ 4.95 U.K.
Phipps Associates
3 Downs Avenue
Epsom. Surrey KT18 5HQ
England
ZX 80 Software:
Pointasketch. Nim, Mothership, Pharoah's
Tomb. XOX. AddMax. SubMax. MultiMax.
DivMax. (decimals-10 digit). Hotel (50 room
bookings). Playmath. Biorhythms.
Send SASE for detailed list and free pro-
gram.
Datalog
20 Aylen Rd.
Portsmouth, England PO3 5HB
England
Z X80 АК Programs:
Star Trek. Pontoon. Adventure - £5.95
(£2.45 each)
M. Bates
Dever Barn
Micheldever
Winchester. Hants
England
Cases for ZX80 Systems
Phoenix Management Services
Paragon House
46 Kent House Lane
Beckenham. Kent
England
ZX80 Software: Moon Lander. Pontoon.
Calendar. Maths test — £ 2
P. Pickering
56 Lennox Road
Todmorden. Lancs. OLI4QD
England
Software Cassette: Random number guess-
ing, Memory Test, Reaction Speed Game,
Hangman — £6.00
Educational Aid Cassette — £ 5.00
Rose Cassettes
P.O. Box 28
Solihull. West Midlands B91 3LU
England
Tutor programs for ІК and 2K Z X80
IK listing — £ 3.00 ($7.00)
2K listing — £ 5.00 ($12.00)
Wyncom
11 Furze Platt Road
Maidenhead Berks. SL6 7ND
Hardware
Interfaces and Printers for the 2 Х80.
Packages from $200.00
CAI Instruments. Inc.
2559 Arbutus Court
Midland. MI 48640
Sinclair ZX80 sales in New Zealand
David Reid Electronics Ltd.
C.P.O. Box 2630
Auckland 1
New Zealand
Sinclair Z X80 sales in Canada
Future Distributors. Inc.
1189 Phillips Square
Montreal. Canada H3B 3C9
Gladstone Electronics
1736 Avenue Road
Toronto. Ontario M5M 3Y7
Full-size keyboard for MicroAce
Fully wired — $85.00
Kit — $65.00
Leonard Holmberg
P.O. Box 6273
Orange. CA 92667
RF shielding kit for MicroAce — $3.00
Outbound Engineering
Р.О. Box 218
Сһап ет. ТХ 75758
Users Groups
Publishes club newsletter. Send self-
addressed. stamped envelope for free
copy.
National ZX80 Users Club
Unit 3
33 Woodthorpe Road
Ashford
Middlesex TW15 2RP
England
SYNC Magazine
David Ahl, Founder and
Publisher of Creative Computing
You might think the term "creative com-
puting” is a contradiction. How can some-
thing as precise and logical as electronic
computing possibly be creative? We think
it can be. Consider the way computers are
being used to create special effects in
movies—image generation, coloring and
computer-driven cameras and props. Oran
electronic ‘“sketchpad” for your home
computer that adds animation, coloring
and shading at your direction. How about a
computer simulation of an invasion of killer
bees with you trying to find a way of keep-
ing them under control?
Beyond Our Dreams
Computers are not creative per se. But
the way in which they are used can be
highly creative and imaginative. Five years
ago when Creative Computing magazine
first billed itself as "The number 1 maga-
zine of computer applications and soft-
ware," we had no idea how far that idea
would take us. Today, these applications
are becoming so broad, so all-
encompassing that the computer field will
soon include virtually everything!
In light of this generality, we take "appli-
cation’ to mean whatever can be done with
computers, ought to be done with comput-
ers or might be done with computers. That
is the meat of Creative Computing.
Alvin Toffler, author of Future Shock and
The Third Wave says, read Creative Com-
puting not only for information about how
to make the most of my own equipment but
to keep an eye on how the whole field is
emerging.
Creative Computing, the company as
well as the magazine, is uniquely light-
hearted but also seriously interested in all
aspects of computing. Ours is the maga-
zine of software, graphics, games and sim-
ulations for beginners and relaxing profes-
sionals. We try to present the new and im-
portant ideas of the field in a way thata 14-
year old or a Cobol programmer can under-
stand them. Things like text editing. social
creabive
competing
A REMARKABLE MAGAZINE
"The beat covered by Creative Computing
is one of the most important, explosive and
fast-changing. "— Alvin Toffler
simulations, control of household devices,
animation and graphics, and communica-
tions networks.
Understandable Yet Challenging
As the premier magazine for beginners, it
is our solemn responsibility to make what
we publish comprehensible to the new-
comer. That does not mean easy; our
readers like to be challenged. It means
providing the reader who has no prepar-
ation with every possible means to seize
the subject rnatter and make it his own.
However, we don't want the experts in
our audience to be bored. So we try to
publish articles of interest to beginners and
experts at the same time. Ideally, we would
like every piece to have instructional or
informative content—and some depth—
even when communicated humorously or
playfully. Thus, our favorite kind of piece is
acessible to the beginner, theoretically
non-trivial, interesting on more than one
level, and perhaps even humorous.
David Gerrold of Star Trek fame says,
"Creative Computing with its unpreten-
tious, down-to-earth lucidity encourages
the computer user to have fun. Creative
Computing makes it possible for me to
learn basic programming skills and use the
computer better than any other source.
Hard-hitting Evaluations
At Creative Computing we obtain new
computer systems, peripherals, and soft-
ware as soon as they are announced. We
put them through their paces in our Soft-
ware Development Center and also in the
environment for which they are intended —
home, business, laboratory, or school.
Our evaluations are unbiased and accur-
ate. We compared word processing printers
and found two losers among highly pro-
moted makes. Conversely, we found one
computer had far more than its advertised
capability. Of 16 educational packages,
only seven offered solid learning value.
When we say unbiased reviews we mean
it. More than once, our honesty has cost us
an advertiser —temporarily. But we feel
that ourfirst obligation is to our readers and
that editorial excellence and integrity are
our highest goals.
Karl Zinn at the University of Michigan
feels we are meeting these goals when he
writes. "Creative Computing consistently
provides value in articles, product reviews
and systems comparisons ...in a magazine
that is fun to read."
Order Today
To order your subscription to Creative
Computing send payment to the appropri-
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Join over 80,000 subscribers like Ann
Lewin, Director of the Capital Children's
Museum who says, “I ат very much im-
pressed with Creative Computing. |t is
helping to demystify the computer. Its arti-
cles are helpfu!, humorous and humane.
The world needs Creative Computing."
creabive
compating
Attn: Cindy
P.O. Box 789-M
Morristown, NJ 07960
Toll-free 800-631-8112
(In NJ 201-540-0445)
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PLUS:
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SYNC is the dynamite bi-monthly magazine for users of the Sinclair ZX80. The main
focus is on applications, programming techniques, hints and tips for getting the most
out of the ZX80. SYNC also reviews new peripherals, software and books for the 2Х80.
Subscriptions to SYNC cost just $10 for six bi-monthly issues (£10 in the U.K.). Send to
SYNC, 39 E. Hanover Avenue, Morris Plains, NJ 07950, USA.
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